vE.W'D
Contents
August 31, 1995.
Editorial.
A Contribution to the Natural Classification of Lower and Middle
Cambrian Arthropods: Food Gathering and Feeding Mec hanisms .
E. L. Bousfield
The Amphipod Superfamily Pontoporeioidea on the Pacific Coast
of North America. II. Family Haustoriidae. Genus Eohaustorius
J. L. Barnard: Systematics and Distrihutional Ecology.
E. L. Bousfield and Phillip M. Hoover
The Amphipod Family Pleustidae on the Pacific Coast of North
America. Part III. Subfamilies Parapleustinae, Dactylopleustinae,
and Pleusirinae: Systematics and Distributional Ecology.
E. L. Bousfield and E. A. Hendrycks
Additions to Amphipacifica Vol. I (4). Eusiridae. Cataloguing data.
35.
1
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AMPHIPACIFICA
JOURNAL OF SYSTEMATIC BIOLOGY
Volume II, Number 1
August 31, 1995
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DEDICATION
The Journal AMPHIPACIFICA is dedicated to the promotion of systematic biology and
to the conservation of Earth’s natural resources.
Cover design: Adapted from the title page of S. J. Holmes (1904). “Amphipod
Crustaceans of the Expedition.”
Harriman Alaska Expedition, pages 233-244.
AMPHIPACIFICA VOL. H NO. 1. AUG. 31, 1995.
EdISt@iro§ill „
Since completion of the first volume of Amphipacifica
last spring, we have continued to receive expressions of both
satisfaction and criticism concerning the quality of its content
and editorial format. The commentary came from a wide
spectrum of readers including: MarkCostello, Dublin, Ireland;
Larry Hamblin, Romford, U. K.; Pierre Noel, Universite de
Paris, France; John Holsinger, Norfolk, VA.; Patricia
McLaughlin, Anacortes, WA; Valerie MacDonald, West
Saamch, Charles Low, Victoria, and Cas Lindsey, Vancouver,
B . C. Jim Lowry, Australian Museum, Sydney, has pointed
out a problem in one of early phoxocephalid plates that
requires clarification. Niel Bruce, University of Copenhagen
Museum, Denmark, has detected a number of editorial
oversights in previous numbers that we have attempted to
correct in this issue. Changes include a repositioning of the
pagination and running head, more restricted use of
underlining, oversize letters, and boldface type, and reduced
use of abbreviations in the references. More careful attention
has been given the alignment of type in parallel columns, and
to consistency in labeling of illustrations. We welcome your
further suggestions for improvement.
As the scope of the journal expands, we encourage
exchange advertising with other journals of systematic biol-
ogy, and with societies and agencies concerned with conser-
vation of natural resources. We welcome submissions of
medium to large systematic studies, and also shorter research
papers and review articles that involve some aspect of
aquatic biology and/or environmental concern. Although
the journal emphasizes systematic research on aquatic
invertebrate faunas of the North Pacific, as noted previously,
publication criteria extend to other biomes (including
terrestrial), other biotas (including vertebrates and fossil
animals) and other regions (including the North Atlantic).
' The first paper of this issue is a contribution to the re-
classification of arthropods and arthropod-like animals, based
on feeding and food-gathering mechanisms. Arthropod-like
fossil animals of the Burgess Shale formation flourished in
ancient Paleozoic seas some 520 million years ago. As a
result of later orogenic processes, exquisitely preserved
fossilized remains of these early crustacean and arachnid-
like animals can be recovered from Middle Cambrian
sedimentary rocks now situated at altitudes of about 1.5 km
a.s.l. This study outlines possible phyletic relationships of
known fossil species within two major groups of arthropods.
These are defined as the uniantennates, including the aquatic
Paleozoic trilobites and modem terrestrial arachnids, and the
biantennates that encompass the mainly aquatic crustaceans,
and modem terrestrial myriapod and hexapods. This enorm-
ous assemblage of joint-legged animals, comprising well
over one million described species, fossil and recent, has
been encompassed within a phyletic subdivision of only 9
superclasses and 29 classes. Quite remarkably, the total
known Cambrian arthropod fauna of less than 100 fossil
species, all aquatic, represents 6 of the superclasses and 14
of the classes, whereas the Recent arthropod fauna of over
1
one million described species, both aquatic and terrestrial, is
contained in only 4 superclasses and 15 classes. Thus, the
contention of Stephen J. Gould, set forth in his popular book
"Wonderful Life" (1989), that the Cambrian fauna exhibited
greater disparity (diversity at high taxonomic level) than at
any other time in animal evolutionary history, finds strong
support in the present analysis.
The second paper in the series treats the sy stematics and
distributional ecology of North Pacific members of amphipod
family Haustoriidae. Among macro-cmstaceans, haustoriids
are one of the most highly modified for a free-burrowing life
style. The family is most diverse within the western North
Atlantic region, especially along the sandy estuarine coastline
of southeastern United States. However, one genus, Eohaust-
orius, has penetrated the North Pacific and is now nearly
equally speciose along Asiatic and North American coastlines.
Its subtidal species occur throughout the Pacfic Rim region.
However, intertidal species are apparently absent from
corresponding Asiatic shores. There, winter conditions are
severe, accompanied by sub- freezing temperature and shore
icing; in summer, species of the competing fossorial talit-
roidean family Dogielinotidae dominate intertidally. Along
corresponding North American Pacific sandy shores, how-
ever, winter conditions are relatively mild, shore icing is
lacking and, in summer, only one species of intertidal dogiel-
inotid occurs, and only along the open coast of Washington
and Oregon states. Their infaunal densities, ease of collect-
ing, and sensitivity to inimical substances, render certain
species of Eohaustorius suitable for bioassay monitoring
and testing of marine sediment toxicity.
The final paper is a continuation of a series of revision-
ary studies on the relatively primitive, benthic, gammaridean
amphipod family Pleustidae. Member species are mainly
micro-carnivores and commensals within marine commun-
ities of sessile invertebrates and attached plants. Subfamilies
Parapleustinae, Pleusirinae, and Dactylopleustinae,
investigated here, are almost wholly endemic to the North
Pacific Brim region. Of the 32 known species combined, all
but two occur nowhere else. The North Pacific marine shelf
is characterized by long-term stability of associated biotic
communities, and equable marine climates. These factors,
presumably operating throughout the evolutionary devel-
opment of the three pleustid subfamilies, are considered
primary in dampening evolutionary thrust in other directions.
In summary, a remarkable feature of these three papers
is the coincidental stratigraphic range of the marine animals
encompassed, from the subtidal to the ocean abyss on the one
hand, and from the supralittoral zone to high interior mountain
slopes of British Columbia on the other.
With respect to the article on Cadborosaurus that ap-
peared in the special supplementary issue of Amphipacifica,
Vol. I, commentary pro and con has been received. A few
excerpts are as follows: "You may have created some
controversy with "Caddy" but . . you'll have provided some
foundation for its recognition and study" (Dale Calder letter,
June 19). "I was most impressed by . . . the paper on
AMPHIPACIFICA VOL. H NO. 1. AUG. 31, 1995. 2
AMFEIP ACIFICA: PERSONAE NOVAE. . .
Cadborosarusu willsi . . . and I should like to distribute it
among our subscribers (Jon Downes, Centre for Fortean
Zoology, U. K.). " . . You were right in publishing. Perhaps,
some day, it might prevent another "Kermode" . . (who
make) hasty, often erroneous identifications" (Earl Godfrey,
Ottawa). The popularized version entitled "Cadborosaurus,
survivor from the deep", Horsdal & Schubart, publishers,
Victoria, 1 34 pp.. May, 1985, was "read with much interest"
by several subscribers and friends, including Ian McTaggart
Cowan, Victoria. Concerning this matter, the resignations of
dissenting editorial associates of this journal, Craig Staude
and Phil Lambert, have been accepted, regretfully. We are
greatly indebted to Craig and Phil for their editorial help with
previous regular issues of the journal, and wish them well in
furthering their invertebrate research objectives.
The authors of the research paper on Cadborosaurus
did not refer to a paper by Peter Scott and Robert Rines in
Nature, 258: 466-468, 1975, in which the Loch Ness phe-
nomenon was newly described as Nessiteras rhombopteryx.
Their reconstruction, based on fixed demersal strobe flash
Marianne Wilkinson, B.A. (Eng), Associate Editor, has
had a varied background in the field of communication and
education. She has served as a high school teacher, news
reporter, freelance writer, designer, and photographer. Fol-
lowing a four-year stint as a humour columnist, she becaame
publisher and editor-in-chief of British Columbia's "Island
Life" Magazine. Her avocational interests include writing,
archeology, paleontology, and the outdoors, and is avid
about flying.
Phillip M. Hoover, BSc., majored in biology at the
University of Victoria, with emphasis on marine pollution
biology and invertebrate taxonomy. During studies for the
MSc degree in biology, he served as a teaching and research
assistant in the laboratory of Dr. Derek V. Ellis with whom
he co-authored studies on the impact and recovery of marine
benthos in mine tailing wastes. Phil recently completed stud-
ies on the systematics of North American Pacific marine
amphipods of families Haustoriidae, Amphilochidae, and
Corophiidae, the first of which appears in this issue.
Production of this issue benefits greatly from the
experienced editorial services of Tara Steigenberger, former
assistant editor. Royal British Columbia Museum, Victoria.
photographs of a partial body, neck and supposed hind
flipper, portrays a thick-bodied, long-tailed animal with two
pairs of large flippers. Such is quite unlike Cadborosaurus
willsi, and the names are thus very probably not synonymous.
Regretably , the Loch Ness specimen was not "in hand" at any
time and, in our view, the photographs are not sufficiently
distinct or complete to form the basis for a reasonably accur-
ate interpretation of the animal’s external morphology.
The difficulty of research here cannot be overestimated.
Acquiring a further large specimen for detailed morphologi-
cal study is very unlikely, but a small juvenile might again be
captured alive and its behaviour studied in a marine aquarium.
Despite several recent sightings in waters of the Saanich pen-
insula, May - August, 1995, neither video footage nor photo-
graphic "still" shots of this species at the water surface were
obtained. However, these new sightings, made independ-
ently, some by two or more observers simultaneously, in-
cluding one from a large deep freshwater lake not far from
Victoria, further support the reality and recurring predict-
ability of this large, anadromous, vertebrate species.
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 3
A CONTRIBUTION TO THE NATURAL CLASSIFICATION OF LOWER AND MIDDLE
CAMBRIAN ARTHROPODS: FOOD-GATHERING AND FEEDING MECHANISMS.
ABSTRACT
by E. L. Bousfield, Research Associate
Royal Ontario Museum, Toronto, Canada MSS 2C6
The classification of arthropods and arthropodlike invertebrates of Lower and Middle Cambrian strata
is currently in a state of flux. Reanalysis of these early arthropods, however, indicates that a more widely
acceptable basis for their natural classification might emphasize mechanisms of food gathering and feeding.
Moreover, such mechanisms are usually readily determinable in both fossil and living specimens.
This study employs a relatively broad definition of the term “arthropod”, and utilizes most higher
classificatory names of the arthropod literature, but with reorganized emphasis. The views of Gould (1989)
and Briggs et al. (1993) concerning high-level taxonomic diversity (disparity) of Lower and Middle Cambrian
arthropods ( sensu Walcott, 1912) are generally supported. However, these taxa have all been classified
previously within accepted arthropod subcategories and none is considered new at the level of phylum or
subphylum. Although the present analysis suggests plausible evolutionary pathways for food-gathering and
feeding mechanisms in uniantennate (i.e., chelicerate) lineages, and possibly in biantennate (i.e., crustacean,
myriapod and hexapod) arthropods, incorporation of these ideas within a suggested formal classification
awaits broader acceptance among current workers.
INTRODUCTION
Arthropods are a major component of a fauna that, dur-
ing the Cambrian Period, attained what has been described
by Gould (1989) as a "maximum disparity of animal life".
This concept, of broad morphological diversity at high tax-
onomic level (here defined as subclass or higher, or undeter-
mined), has been questioned in detail by several (e.g., Ridley
(1990, 1993; Briggs et al. (1992), but ably defended by
Gould (1993) and Foot & Gould (1992). Thus, disparity of
arthropods and arthropod-like forms does not appear to have
been greater in Cambrian than in Recent times, whatever
classifications are consulted or methodologies used (Wills et
al., 1994). However, in proportion to the small number
(< 1 00) of Cambrian arthropod species recorded to date, from
a half dozen or so major fossil sites world- wide, the percent-
age of high-level taxa that they represent is very much higher
than that of comparable samples of Recent faunas. If
considerations are restricted to aquatic faunas only, the
percentage difference is even higher. Whatever the magni-
tude of these differences, however, the Cambrian Period can
fairly be viewed as ^ period of arthropod evolutionary
"explosion".
Cambrian arthropods are mostly unlike living repre-
sentatives of the phylum, and therefore difficult to classify
on existing natural bases. One of the richest arthropod as-
semblages, of about 35 species, has been described from
Middle Cambrian Burgess Shale deposits in Yoho National
Park, British Columbia (Conway Morris & Whittington,
1985). General and popularized treatments of that fauna, by
Gould (1989) and Briggs et al. (1993), have summarized the
original work of Charles Walcott (1912), and the subsequent
careful descriptive treatments by Whittington (1971, 1975),
Bruton (1981), Briggs (1979, 1981); Briggs & Whittington
(1983, 1987), Collins (1987a, b), Collins & Rudkin (1981),
Conway Morris (1986) and others. Their work has made
possible the present re-analysis of the etaly arthropod fauna
for which the author feels most grateful.
Previous work has revealed a plethora of Cambrian tax-
onomic oddities several of which, according to Gould (1989),
may require new higher classification, even at the level of
phylum. Gould accepted, justifiably, the morphological
interpretations of the aforementioned principal workers in
this unfolding paleontological drama. Recent field work,
especially in the Chengjiang region of southern China (Hou
et al . 1991), and in Greenland (Conway Morris et al . 1987),
has yielded many more important new taxa (e.g., by Hou, 1987
a, b; Hou & Bergstrom, 1991; Chen, etal. 1994). During his
relatively brief two-year book-compilation period, Gould
(1989) touched on the initial papers by Hou; however, he did
not reference other pertinent works of group specialists (e.g.
of Bergstrom, 1986; Schram, 1986; Dahl, 1984, 1987) that
embody alternative and possibly more plausible classifica-
tions and evolutionary starting points, as suggested by the
writer (Bousfield, 1987), for some of the major Burgess
arthropod groups. Some reviewers (e.g., Fortey, 1989) have
pointed to papers on cladistic classificatory methodology
(e.g., Briggs & Fortey, 1989) that do provide credible, but not
entirely correct, classifications of some of the enigmatic
groups contributing to Gould’s high disparity levels.
Delle Cave & Simonetta (1991) analyzed previous stud-
ies in a well illustrated and comprehensive account of early
Paleozoic arthropods. They emphasized the importance of
functionality, specially the the role of feeding appendages in
the evolution of arthropod morphotypes. For the most part,
their taxonomic groupings and evolutionary charts bring
perceptive and cohesive insight to some mini-groups (e.g.,
trilobitomorphs, the Sanctacaris problem, and the Scanian
larval stages), and stress the need for authors to name new
taxa, whatever the later higher categories might be. How-
ever, they did not differentiate between food gathering and
feeding (masticatory) roles and, as summarized in their
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 4
Table IV, apparently missed the significance of relationships
within the Dicephaiosomala and the overall relationships
between anomalocarids and primitive trilobitomorph as-
semblages (which they did recognize) such as the Yohoiida
and Leanchoiliida. Briggs et al (1993) continued with a
conservative classification of early arthropods (p. 6) in
which several previous higher taxa were not recognized and
the anomalocarids omitted entirely. Whatever the merits or
weaknesses of these various treatments, collectively they
underscore the state of flux that presently characterizes early
arthropod classification.
The purpose of this paper is to provide a classification
that reflects more closely the actual degree of biological
disparity and the major evolutionary themes within the
Cambrian arthropod fauna. It also attempts to reveal, in more
detail than previously, the relationship between form and
food-gathering and feeding functions in selected Lower and
Middle Cambrian arthropods and their descendent groups.
ACKNOWLEDGEMENTS
This study has taken place during a 10-year association
with Dr Desmond E. Collins at the Royal Ontario Museum
(ROM), Toronto, for whose tactful guidance and perceptive
stimulus the writer is most grateful Dr David Rudkin
(ROM), Derek Briggs (University of Bristol, U.K.), Jan
Bergstrom (Natural History Museum, Sweden), Jarmila Kuk-
alova-Peck (Carleton University, Ottawa), Frederick R.
Schram (Institute of Taxonomic Studies, Netherlands) and
several others, have directly or indirectly provided helpful
input to the text. Earlier drafts of the text have been helpfully
reviewed by C.R.Harington and Stephen Cumbaa (Canadian
Musem of Nature (CMN), Ottawa), Murray Copeland and T.
E. Bolton (Geological Survey of Canada (GSC), Ottawa),
and A. L. Hamilton (Biosystematics, Agriculture Canada).
Lisa Bohach (Earth & Ocean Sciences, University of Victoria)
has provided perceptive commentary and editorial services,
and references not previously available to the author.
In the preparation of composite illustrations here I have
been privileged to adapt, with warmest appreciation, the or-
iginal text illustrations of D. E. G. Briggs, H. B. Whittington,
D. E. Collins, F. R. Schram, X. Hou, L. Delle Cave, A.
Simonetta, and several other primary sources.
In parallel to the present study, Professor Edward Laidlaw
Smith, San Francisco, CA, has combined and collated pre-
vious arthropod categories in a detailed phyletic classific-
ation of arthropods (Atlas of Insect Anatomy, unpublished).
Since this study has resulted in some similar classificatory
conclusions. Dr Smith has generously permitted detailed
reference to and use of updated non-insect arrangements in
this text, for which I am most grateful.
SYSTEMATIC PREAMBLE
The term “arthropod” is here defined as an invertebrate
having an externally segmented body that bears one or more
pairs of j ointed appendages. The body consists of head and
trunk regions, of which the latter may be tagmatized or sub-
divided into thorax and abdomen, mesosome and metasome,
pygidium and/or telson, according to the taxonomic group.
In primitive aquatic arthropods, the head always bears an
acronal segment (first, or protocerebral somite) that is always
pre-oral in position, having sensory organelles but no jointed
limbs. The first true head segment (second or deutocerebral
somite) is limb bearing, and usually pre-oral in active life
stages. The head may also encompass up to five (rarely six)
additional limb-bearing segments, the first of which (third or
tritocerebral somite) may appear pre-oral in position. The
post-oral appendages of head and trunk are primitively or
embryologically biramous, the segments of which are exter-
nally chitinized, sclerotized or mineralized. The inner ramus
is usually locomotory, food gathering or masticatory, and the
outer ramus usually respiratory in function. Growth pro-
ceeds by moulting of the ectoderm (ecdysis). Following
Bergstrom (1986, 1987) and Chen et al. (1994), true arthro-
pods here embrace the primitive Cambrian dicephalosomatid
genera Anomalocaris, Opabinia, Cassubia and close rela-
tives. However, contrary to the views of Snodgrass (1956)
and Manton (1977), true arthropods do not include the
Tardigrada nor the Onycophora in which the body is not
externally segmented and the post-oral limbs, although
dactylate (clawed), are not jointed nor biramous.
The Middle Cambrian macro-arthropod fauna is charac-
terized by a high percentage of primitive body forms that,
superficially, appear to be intermediate between true worms
(phylum Annelida) and higher groups of aquatic arthropods
such as the Chelicerata and Crustacea. Paradoxically per-
haps, some of these early forms (e.g., Opabinia) show a
remarkably high degree of specialization of body form and
function that tends to mask their true phyletic affinities. In
adult stages of some primitive modem arthropods (e.g.,
Remipedia) and larval stages of cirripedes, phosphatocopine
ostracods and skaracarids, the acronal segment bears conspic-
uous frontal organs or frontal filaments of presumed sens-
ory function, and/or a median naupliar eye (Schram, 1986).
The acronal somite is especially well developed in skaracarid
crustacean larvae (e.g., Martinssonia Muller & Walossek,
1986). However, in arachnids, myriapods and hexopods, the
acron is considered embryonic and fused with the second
head somite in active hfe stages (Savory, 1964).
The first tme head segment (second somite) of arthro-
pods bears one pair of limbs, of 1-14 basic segments, that is
embryonically uniramous and pre-oral. These limbs may be
stout, the segments spinose or toothed, or apically pincer-
like and raptorial in function, as in chelicerates and their
presumed precursors. However, more often they are
filamentous and sensory in function, as in the "antennae" of
trilobites, and the antennules of crustaceans and their pre-
sumed ancestors, and marrellomorphs. In some Cambrian
arthropods (Q.g., LeanchoiliaX the appendage appears distally
multi-flagellate. In higher cmstaceans (Malacostraca), the
antennules are often secondarily biramous (e.g., in
Eumalacostraca), and occasionally triramous (in Stom-
atopoda). In myriapods and insects, the antennae are
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995
uniramous, filamentous and sensory. In no instance, however,
are these appendages gnathobasic.
The third head somite (rarely lacking except in a few
Cambrian species such as Opabinia and Sidneyia) bears a
pair of limbs homologous with the antennae of crustaceans
and early biantennate arthropods. These limbs, homologous
also with the pedipalps of chelicerates and pycnogonids,
may be uniramous or, as in the intercalary (supralingual)
segment of myriapods and hexapods, vestigial or essentially
lacking. In primitive arachnids and early precursors, and in
larval stages of crustaceans, limbs of the third head somite
are masticatory as well as locomotory and/or respiratory in
function. Thus, as will be demonstrated in Cambrian
aquatic arthropods (below), the evolutionary trend in func-
tioning of the first two pairs of appendages in arthropods
progresses from food gathering and mastication, to food
sensing and tactilility.
The head segment and limb homologies employed in
this study, and suggested classification (pp. 23-27), conform
with classical concepts of arthropod head structure, innerva-
tion and embryology (e.g., of Borradaile & Potts, 1941;
Savoiy, 1964; Bergstrom, 1979). Kukalova-Peck (1987)
and Smith (1990) have fused the acronal segment of hexa-
pods with the labrum to form the clypeolabral, or first
(protocerebral) somite which, in Upper Carboniferous
monurans, appears basolaterally segmented. The second
head somite remains the antennal (deutocerebral) somite,
homologous with the antennular somite of crustaceans.
However, Smith (loc. cit.) has suggested that the chelicerae
of arachnids originate on the third (tritocerebral, supralingual)
somite, and the pedipalps on the fourth or mandibular seg-
ment, resulting in eight prosomal somites, one more than the
normal maximum recognized by all other authors.
In Cambrian arthropods, the anterior portion of the gut
is typically deflexed and the mouth usually opens ventrally
on the head. In a few groups, however, (e.g., Jianfengia,
Sanctacaris) the mouth appears to open apically or frontally
(Hou, 1987a, Biiggs & Collins, 1988). Body segmentation
may not always be externally visible, especially in larval
forms, or in highly modified adults (e.g., some internal
parasites). Paired limbs of the trunk are primarily biramous,
but may be secondarily uniramous. The branches may be
variously modified, unsegmented, or lacking (e.g., in early
growth stages and in adults of various taxonomic groups).
Thus, in a biramous limb, the outer branch may be lightly
chitinized and flaplike (unsegmented) in swinuning forms
or, when the outer is respiratory in function, the inner branch
may be fully segmented, leglike, and heavily calcified or
mineralized, especially in heavy bodied benthic forms. As
noted above, some post-oral paired appendages may be
gnathobasic wherein the coxa and/or adjacent segments are
medially toothed, or the entire limb reduced and modified as
a specialized mouthpart (e.g., mandible or maxilla). Such
feeding appendages are tagmatized as part of the cephalon.
Morphological differences between major groups of
arthropods are fully as great as between accepted subphyla
5
and classes within other major phyla (e.g., as between
chitons and cephalopods within phylum Mollusca). In
Lower Cambrian to Lower Ordovician times (530-500
m.y.b.p.), major groups of arthropods having modem repre-
sentatives (e.g., Chelicerata, Crustacea) were then in what
might be termed a primordial or early state of evolution or,
in the case of Myriapoda and Hexapoda, unrecognized as
such. Thus, true crustaceans were represented in the Cambrian
fossil record only by the Maxillopoda (Ostracoda, Cirripedia,
and skaracarid larval forms) (see Schram, 1986 in part; Dahl
1984, 1987). Members of the Aglaspida (Upper Cambrian)
were considered by Bergstrom (1979) to be early chelicerates
but Briggs et al. (1978) demonstrated the filamentous nature
of the "chelicerae" and removed the Aglaspidida from the
merostomes. The earliest chelicerates are Chasmataspis, or
perhaps Triopus, from the Lower Ordovician (Fig. 8). Other
major arthropod groups (e.g. Myriapoda, Hexapoda) were
recognizable in late Silurian and early Devonian times, when
freshwater and terrestrial fossils deposits were first identiifed.
PREVIOUS CLASSIFICATIONS
Several different classifications of Cambrian macro-
arthropods have been proposed, four of which are presented
in Table 1. The 17 sample species listed here were classified
initially by Walcott (1912) who “shoehorned” them (fide
Gould, 1989) into a relatively few existing crustacean and
arachnid subcategories (Column 1). Over the next 75 years
the species were classified variously by Stdrmer (1959),
Sharov (1966) and Bergstrom (1979), and incorporated by
Edward Laidlaw Smith in a forthcoming “Atlas of the
Insecta”, communicated to the writer, with kind permission,
for comparative purposes here (Column 4). Despite previous
designations, Gould (1989) regarded these forms as highly
distinctive, belonging to two new phyla; 12 unique arthropods;
one chelicerate arthropod; one trilobite; and one malacost-
racan (Column 2). Briggs et al.( 1993) had retreated into a
somewhat similar conservative listing of Cambrian
arthropods, a list that did not include Opabinia,
and other dicephalosomatid forms (Column 3). The E. L.
Smith listing (Column 4) would place 15 of Gould's new or
unique taxa within long-established classes of crustaceans,
trilobitoids, protochelicerates, and chelicerates, five of them
more or less within Walcott's original categories. However,
as we may note in the following text, Smith's placement of
Marrella mdBranchiocaris within the protochelicerates,
and Odaraia andCanadaspis within the Crustacea, is inter-
preted otherwise here.
Mechanisms of food-pgathering and feeding.
In assessing the overall legitimacy of these classifications,
we might conclude that, under the circumstances of the
relatively limited systematic knowledge of his day, Charles
Walcott was remarkably perceptive in much of his classifi-
cation. Although thereticenceofGouldandBriggstorefine
AMPHIPACMCA VOL. 11. NO. 1 AUG. 31, 1995 6
TABLE L THE CLASSIFICATORY STATUS OF SOME BURGESS SHALE FOSSIL GENERA
Genus Name
Higher category by Author
Walcott (1912)
Gould (1989)
Briggs et al (1993)
E.L.Siiiith C'Atlas" prep)*
Marrella (Wale.)
near Trilobita
unique
Arthropod
Protochelicerata Stormer, 1944
arthropod
(primitive)
CL. Marrellidea Walcott 1912
Yohoia (Wale.)
branchiopod
unique
Arthropod
Protochelicerata Stprmer, 1944
crustacean
arthropod
(other)
CL. Yohoiidea Henriksen 1928
Opabinia (Wale.)
branchiopod
new
Unassigned
Protochelicerata Stprmer, 1944
crustacean
phylum
Invertebrate
CL. Probosciferidea Sharov 1966
Burgessia (Wale.)
branchiopod
unique
Arthropod
Trilobitoidea St0rmer, 1955
crustacean
arthropod
(other)
0. Nectaspida Raymond, 1920
Branchiocaris (Wale.)
malacostracan
unique
Arthropod
Protochelicerata St0rmer 1944
crustacean
arthropod
(primitive)
CL. Branchicaridea
Canadaspis (Wale.)
phyllocaridan
malac-
Crustacea
Crustacea Pennant 1777
crustacean
ostracan
CL. Branchiopoda Latr. 1817
Naraoia (Wale.)
branchiopod
soft-bodied
Trilobita
Trilobitoidea St0rmer, 1955
crustacean
trilobite
0. Nectaspida Raymond 1920
Odaraia (Wale.)
malacostracan
unique
Crustacea
Crustacea Pennant 1777
arthropod
CL Pranchiopoda Latreille, 1817
Sidneyia (Wale.)
merostome
unique
Arthropod
Protochelicerata St0rmer 1944
arthropod
(other)
CL. Sidneyiidea Walcott, 1912
Malaria (Wale.)
merostome
unique
Arthropod
Trilobitoidea St0rmer, 1955
arthropod
(other)
incertae sedis
Habelia (Wale.)
merostome
unique
Arthropod
Trilobitoidea Stprmer, 1955
arthropod
(other)
incertae sedis
Actaeus (Wale.)
unknown
unique
Arthropod
Protochelicerata St0rmer, 1944
arthropod
(other)
CL. Leancholiidea Raymond!
Alalcomanaeus (W.)
unknown
unique
Arthropod
Protochelicerata St0rmer, 1944
arthropod
(other)
CL. Leanchoiliidea Raymond!
Emeraldella (Wale.)
merostome
unique
Arthropod
Protochelicerata St0rmer, 1944
arthropod
(other)
CL. Emeraldellidea Raymond!
Leanchoilia (Wale.)
branchiopod
unique
Arthropod
Protochelicerata St0rmer, 1944
crustacean
arthropod
(other)
CL. Leanchoiliidea Raymond!
Sanctacaris (Briggs &
N/A
chelicerate
Chelicerata
Chelicerata Heymons 1901
Collins)
arthropod
Arachnida Lamarck, 1801
Anomalocaris (Wale.)
branchiopod
new
Unassigned
Protochelicerata St0rmer, 1944
-1- Laggania
phylum
Invertebrate
CL. Anomalocaridea Raymond!
+ Peytoia
+ appendage F ^
Selected names with permission of E. L. Smith (references not detailed here); ! - Raymond, 1935.
the classification with new terminology is to some extent
justified, Smith's listing of previous formal categories indi-
cates that their reticence does not provide a helpful solution
to the problem. The need seems greatest for more careful
and more rigorous definition of existing categories, based on
principles of functional morphology where possible, and a
resort to new categories when existing or redefined catego-
ries prove inadequate. As Gould (per Schram, 1990) reminds
us, errors and oversights of the past are part of the process
of getting the probably correct answer, and so provide a
prime stimulus for the present undertaking.
Gould (1989) noted that previous workers on Cambrian
arthropods seemed reasonably confident of their classifica-
tion of the most primitive forms, e.g., the Onycophora, and
the presumably most advanced major taxon, the Trilobita.
However, they seemed less certain of other arthropods
variously attributed to the Crustacea (ie. Canadaspidida,
Branchiocarida) or having only general similarities with the
Trilobita. The greatest difficulties were encountered with
forms having both annelid-like and arthropod-like features
(e.g. Anomalocaris, Opabinia). Charles Walcott (1912)
utilized subcategories of extant arthropod groups (e.g.,
Branchiopoda, Ostracoda -t- Merostomata). St0rmer(1944,
1959) proposed new “catch-all” categories (e.g., Trilobit-
oidea) for many enigmatic forms. These classifications
utilized standard character states such as body tagmatization,
number of paired head (or head shield) appendages, types of
appendages (biramous, gnathobasic, gill-like) and larval
biology, to the hmit of existing knowledge, but did not
emphasize fimctionahty or possible behavioural significance.
AMPHIPACIFICA VOL. U. NO. 1 AUG. 31, 1995
7
Bergstrom (1979, et seq.) employed the term
“Schizoramia” to encompass all Trilobitomorpha (Trilobita,
Merostomatoidea, and Chelicerata). These are characterized
by primitively biramous trunk limbs of which the endopod is
gnathobasic, and the exopod bears lamellar spines. The
enigmatic genus Emeraldella, having gnathobasic post-oral
legs, was included here, as well as the Marrellomorpha, but
the latter group primarily lacks gnathobasic limbs. The
Pycnogonida (Pantopoda) was not related to any particular
arthropod group. Commendably, Bergstrom relegated
binia and Anomalocaris to the status of a “pre-arthropod”
stock, but later (1986, 1987) decided they were indeed
arthropods, a view now firmly supported by the recent work
of Chen eLal (1994). However, Bergstrom employed the
term Uniramia to encompass both the soft-bodied, externally
annulated onychophorans, and the hard-bodied, externally
segmented myriapods and hexapods having whole-limb
jaws. This concept is now proving flawed and untenable as
a category of natural classification (see Kukalova-Peck,
1992). Onychophorans, early forms of which did exist in
Cambrian seas, resemble the Tardigrada in having shaft-like,
primitively uniramous limbs and pharyngeal teeth or spines,
whereas myriapods and insects have segmented, primitively
biramous limbs, and mouthparts modified from biramous
limbs. Furthermore, Bergstrom’s doubts that biramous and
mandibulate crustaceans arose from the same gnathobasic
limb stock as hexapods are not supported here nor by some
other workers (e.g., Kukalova-Peck, 1987). Imperfect
fossilization has so far prevented determination of the precise
nature of locomotory limbs of dicephalosomatids However,
such is not here considered a major impediment to phyletic
implications of the better preserved, clearly "arthropodized"
feeding appendages of the head region, nor overall relation-
ships with confirmed early biramous arthropod groups.
In assessing the impact of feeding processes on the
evolution of body form in arthropods, a definition of terms
is prerequisite. The entire feeding process encompasses
food-gathering and food-consumption mechanisms. The
food-gathering mechanism is the process by which food
items are entrapped and brought to the mouth region. The
food-consumption (feeding) mechanism is the process of
mastication, the external means by which food items are
rendered suitable for entry into the digestive tract proper.
Basic types of feeding processes of arthropods and their
presumed antecedents are illustrated in Fig. 1. In errant
poly chaete worms (Q.g.^Nereis, Vefit/iej), a taxonomic group
"classically” presumed ancestral to the arthropods, the head
consists of a prostomium and usually a peristomial segment
bearing food-sensing tentacles. No paired limbs, segmented
or otherwise, are involved in food gathering or in food
mastication; these processes are entirely pharyngeal (Fig.
lA). The mechanism consists of an eversible pharyngeal
proboscis, the everted distal end of which is armed with
strong teeth or “jaws” by means of which the food material
(prey organism) is captured and killed. As the proboscis
retracts, it re-inverts, taking in the prey and partly macerating
it by means of other teeth lining the pharynx wall. The food
is then passed rearward to the digestive gut proper. No true
arthropods conform with this category.
In very primitive uniantennate arthropods, (e.g.,
Anomalocaris, Fig. IB . 1 ), food is gathered by the large, spin-
ose and multi-segmented, pre-oral paired appendages. These
capture and transfer prey organisms posteriorly to the mouth
region that opens immediately behind the first true head
segment. The actual feeding mechanism, however, remains
entirely pharyngeal; no paired mouthparts or leg gnathobases
are present, although in the related Opabinia regalis (Fig.
1B.2), some prey items may be partly macerated by the pre-
oral clawed appendage. In the anomalocarids, food is initi-
ally macerated by means of peribuccal teeth, and/or stout
teeth or spines lining the anterior walls of the pharynx, as in
some polychaetes. This feeding process is analogous, or
perhaps even homologus, to mechanisms elsewhere among
living arthropods in the pycnogonids, and among other
invertebrates in the cephalopod molluscs (Borradaile &
Potts, 1941). In cephalopods, the “head-foot” appendages
(tentacles) grip, but do not masticate, the prey by means of
specialized suckers, rather than spines; modified anterior
pharyngeal teeth, the horny beaks, and smaller radular teeth
masticate the prey items just inside the mouth entrance.
In more advanced uniantennates (e.g. in chelicerates.
Fig. 1C), food gathering is also the prime function of post-
oral head (prosomal) appendages, and/or the cheliform pair
of pre-oral appendages. In primitive aquatic chelicerates
(e.g., merostomes), the food is first macerated externally by
means of a grinding action of the gnathobasic coxae of the
paired head and/or trunk appendages. In more advanced
terrestrial arachnids that secondarily lack leg gnathobases,
the killing bite and maceration of the prey is performed by the
distally clawed first post-oral appendages, the pedipalps and/
or the pre-oral chelicerae (Savory, 1964).
Within advanced biantennate (mandibulate) arthropods
(e.g., malacostracan crustaceans. Fig. ID), the pre-oral and
first post-oral appendages are flagellar and food-sensing.
Food is gathered mainly by the anterior trunk (thoracic)
limbs. Swimming, and often respiratory functions may be
relegated to the posterior trunk (abdominal) limbs. Food is
macerated by specialized post-oral limbs of the head region,
the mandibulate mouthparts. Other branches or lobes of
post-oral head appendages may serve in locomotion, and/or
respiration, especially in adults of more primitive groups
(e.g., cephalocaridans) and in larval stages of advanced
forms. Food mastication may also become the primary func-
tion of one to three pairs of anterior trunk limbs, serving as
maxillipeds (e.g., in Decapoda), or as gnathopods (e.g., in
Amphipoda). In their larval stages (e.g., nauplii, metanauplii)
the biramous first post-oral appendage (antenna 2) usually
retains a function in food gathering and mastication, as well
as locomotion (Schram, 1986).
AMPHIPACMCA VOL. D. NO. 1
AUG. 31, 1995 8
oc;ipitot onttnnoi
RAPTORIAL TEETH
(JAWS)
PARAGNATHS
(LATERAL TEETH)
A. PHARYNGEAL
PRE-ORAL HEAD LIMB
(CHELICERA)
RAPTORIAL
PRE-ORAL LIMB
RAPTORIAL "CLAW"
(FUSED PRE-ORAL
HEAD LIMBSl
-ORAL
HEAD LIMBS
(MOUTH -
PARTS)
POST-ORAL
HEAD LIMBS
(GNATHOBASIC)
Limulus
C. CHELICERATE PRE-ORAL
GNATHOBASIC POST-ORAL
TRUNK LIMBS
( GILL BOOKS )
GILL BOOKS ANUS ANUS
PLEOPODS
ANUS
TELSON ■
Orconectes
D. ANTENNAL PRE-ORAL
MANCHBULATE POST-ORAL
FIG. 1. BASIC TYPES OF FOOD-GATHERING AND FEEDING MECHANISMS IN AQUATIC
ARTHRO PODS. A. Polychaete (ancestral). B. Primitive uniantennate arthropod.
C. Advanced uniantennate arthropod D. Advanced biantennate arthropod
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 9
TABLE II. SELECTED GENERA OF CAMB RIAN UNIANTENNATE ARTHROPODS
CATEGORIZED BY FOOD- GATHERING AND FEEDING MECHANISMS
SEGMENTED LIMBS
LACKING
1 .
SEGM
ENTED PRE-AND POST-ORAL LIMBS
II.
PRE-ORAL LIMBS
RAPTORIAL
Ml
PRE-ORAL LIMBS
TRANSITIONAL
IV.
PRE-ORAL LIMBS
FILAMENTOUS
V.
PRE-ORAL LIMBS
CHELICERATE
PHARYNGEAL
MASTICATION
PHARYNGEAL
MASTICATION
TRANSITIONAL
PHARYNGEAL
MASTICATION
GNATHOBASIC
MASTICATION
GNATHOBASIC
MASTICATION
POLYCHAETA
TARDIGRADA
ONYCHOPHORA
Halluctgonia
AyshaaSa
ENDOPODS LOBATE
OR SMOOTH
Anomalocaris
Laggania
Opabinia
t Tulllmonstrum
Casaubla
Jianfengia
Yohoia
ENDOPODS SPINOSE
Leanohollla
Acanthomaridlon
Actaeus
Alalcomanaeua
Sldneyla
Burgessia
Molaria
Habelia
Tegopelte
Naraola
TRILOBITA
Sanctacaris
Emeraldella
Aglaapis
Chaamataapla
t MEROSTOMATA
t EURYPTERIDA
t 8CORPIONIDA
t PYCNOGONIDA?
t Ordovician and later
Selected uniantennate arthropods of the early Paleozoic
are grouped according to categories of food gathering and
feeding outlined in Table II. As noted previously, unassisted
pharyngeal feeding typifies polychaetes and pararthropods
such as the tardigrades and onychophorans (Column I). The
dicephalosomatid arthropods (Column II) utilize only rap-
torial pre-oral appendages in food gathering and/or prelimi-
nary food mastication. They feed in an essentially similar
pharyngeal manner, except that the mouth opening is deflexed
ventrally in anomalocarids and proboscoideans, and opens
anteriorly (or nearly so) in Yohoiida (Hou, 1987a). In prim-
itive trilobitomorphs, the Leanchoiliidacea (Column III), the
post-oral head and trunk limbs appear capable of capturing
and holding food items but feeding is still essentially pharyn-
geal. In the advanced species Alalcomenaeus, post-oral
limbs are essentially gnathobasic (Delle Cave & Simonetta,
1991). In advanced trilobitoideans, includin Sidneyia, the
Burgessiida, trilobites, Emeraldellida and Sanctacarida (Col-
umn IV), the pre-oral appendages become essentially singly
filamentous in form and presumably chemosensory and
thigmotactic in function. The post-oral head and trunk limbs
become fully gnathobasic (although remaining biramous)
and presumably assisted in both food capture and food
mastication. The chelicerates are a final stage in the uni-
antennate feeding series (Column V). The raptorial pre-oral
limbs are reduced to two to four segmented chelicerae, and
the post-oral head limbs are fully gnathobasic and essentially
uniramous. Both types of head appendages may assist in
food gathering and food maceration, especially in the terres-
trial arachnid subgroups. The anterior post-oral trunk limbs
are essentially uniramous; the endopod is lost, but the exopod
remains functional in respiration.
This tabular arrangement of taxa according to feeding
style parallels an increasing evolutionary sophistication of
head and trunk segmentation, and form and function of their
appendages as detailed in pages 11-14. It also matches the
? Head limbs not gnathobasic
fossil track record of the uniantennate groups (Table V, p.
28). Thus, the most primitive feeding styles, as in the
dicephalosomatids, persisted little beyond the Cambrian
Period and not beyond the Palaeozoic Era. By contrast, the
most advanced uniantennate feeding types expanded into the
chelicerate taxa of Ordovician and later periods, including
the remarkably diverse terrestrial arachnids of Tertiary and
Recent times.
Evolution of Post-oral Limb Morphology
The changing structure of the post-oral head and trunk
appendages of uniantennate arthropods is depicted in greater
detail in Figure 2. Within the Dicephalosomatida, the
Anomalocarida and Probosciferida were equipped with pairs
of closely approximated paddlelike plates on each side, not
clearly joined at the base, and perhaps not technically, even
if functionally, forming a biramous limb. The upper plate
(in Opabinm, Fig. 2B, C) was fringed with lateral lamellae,
presumably respiratory in function. The head of Opabinia
(2B, C; 7C.l)lacked post-oral plates, but the three pairs of
post-oral head plates in Anomalocaris (Fig. 2 A) are consid-
ered homologus with the trunk plates. In Cassubia (Fig. 3),
considered here (and by Smith, "Atlas" unpubl.) as a benthic
anomalocarid with relatively short stout pre-oral limbs, the
head may be two segmented. Trace elements alongside the
trunk may be ambulatory endopods of the posterior head and/
or anterior trunk segments. In Yohoiida, including the multi-
segmented Jianfengia from the Lower Cambrian of China
(Fig. 7G), the head bore 3 pairs of post-oral appendages of
which the endopod was 7-segmented, cylindrical, and pre-
sumably ambulatory. The limbs were not demonstrably
gnathobasic, but the ectoderm was sclerotized or mineralized,
with a gill-like exopod, much as in a trunk limb of the
biantennate genus Marrella (Fig. 2D). An exopod was
present andfoliaceous in head limbs of the ^longnt^ Jianfengia
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 10
FIG. 2. BILOBATE AND BIRAMOUS POST-ORAL (HEAD AND TRUNK) LIMBS
OF PRIMITIVE ARTHROPODS OF THE EARLY PALEOZOIC ERA.
A. Anomalocaris (section) B. Opabinia (dorsal) C. Opabinia (lateral)
D. Marre(&i(trunk section) E. ( post-oral section) F. L. (trunk section)
G. Sidneyia (post -oral section) H. TnorlArus (trunk limb) J. LimulusQeRl)
AMPHIPACIFICA VOL. D. NO. 1 AUG. 31, 1995
11
but apparently lacking in those of the relatively short-bodied
and more advanced Yohoia. Trunk limb exopods were
broad, as in the trilobitomorph Leanchoilia (Fig. 2E, F), and
margins setose, as in Sanctacaris (Fig. 6). At least the first
pair, and possibly up to 1 0 pairs, of anterior trunk limbs bore
a cylindrical ambulatory endopod.
Within the primitive transitional trilobitomorphs, in-
cluding the Leanchoiliidacea and Actaeida (Figs. 2E, F), the
3 pairs of post-oral head limbs, and all trunk limbs, developed
strong spines on the inner margins of the segments of the
endopod. The spines were presumably used in grasping and
holding prey organisms, much in the manner of the thoracic
leg spines of eusirid amphipods and adult dragonflies. In
more advanced groups of trilobitoids, the post-oral hmbs of
head and trunk became fully gnathobasic, in which strong
teeth or spinose processes developed on the proximal (coxal
and basal segments) of the endopod. The distal claws of the
endopods functioned in seizing, and the gnathobases in
killing and masticating, prey items prior to transfer to the
mouth proper. In Sidneyia (Fig. 5D), the head lacked post-
oral limbs but the anterior four pair of trunk limbs were
strongly gnathobasic and uniramous, the remaining trunk
limbs biramous. In Burgessiida and in the Trilobita proper
(Fig. 2H), the 3 pairs of post-oral head limbs remained fully
biramous and multifunctional. The outer ramus bore numer-
ous respiratory lamellar spines. In the Emeraldellida, includ-
ing Emeraldella (Figs. 6E, 7M) and Sanctacaris (Figs. 6, 7L)
the anterior two trunk segments became fused to the head,
resulting in 5 pairs of post-oral head appendages. As the
locomotory and respiratory functions decreased and rapto-
rial and masticatory functions of the head limbs increased,
the endopods became more powerfully raptorial and
gnathobasic, whereas the exopods became vestigial, as in
Sanctacaris. In the aquatic chelicerates, the merostomes
(e.g. Limulus, Fig. 2J), the head region similarly bear five
pairs of strongly gnathobasic, ambulatory and essentially
uniramous limbs. However, the pre-oral limbs of merostomes
are chelicerate, not filamentous, and derived from very
different ancestral uniantennates (seepage 12). In all but the
most prinutive aquatic merostomes, the trunk endopods lost
their ambulatory function and disappeared, whereas the
anterior pairs of trunk exopods remained functional in the
form of book gills and, in terrestrial derivatives, book lungs.
In the above evolutionary sequences, the development
of gnathobasic limbs may have been a consequence of im-
proved efficiency in exploiting, as food, hard-shelled prey
living in soft bottom sediments. The feeding style of
Limulus still follows this original primitive pattern.
Evolution of Food-Gathering Appendages
Within uniantennate arthropods, the morphological and
functional forms of pre-oral food-gathering and food-sens-
ing appendages may be linked in possible evolutionary path-
ways (Fig. 3). The presumed ancestral form of this
cephalopod-style food-gathering mechanism is the large
multi-segmented raptoral form typical of species of Anomalo-
caris (Figs. 3A, D). Despite anomalies of fossil limb pre-
servation, the primary plane of motion is presumed to be
essentially vertical. The paired limbs combined, nearly in
parallel, to form a raptorial basket in which prey organs were
captured and killed by the daggerlike posterior (inner) mar-
ginal spines (Collins, 1987). The food items were then
transferred posteriorly, by deflexion and retraction of limbs,
to the masticatory buccopharyngeal teeth of the mouth
region. This plane of action contrasts with the nearly
horizontal or oblique position of the natatory trunk limbs or
lateral lobes of epi-benthic animals. In benthic species, in
which the endopods of post-oral head and trunk limbs were
mainly ambulatory and vertical in position, the pre-oral
appendages were essentially co-planal. In "Laggania "-like
animals (Table I - A. nathorsti group), with 11 -segmented
limbs, the posterior marginal spines were exceptionally long
and strong, as if utilized in raking or digging in soft sediments
(Fig. 3D).
If the plane of action is rotated to the horizontal, the
paired limb spines come into opposition as a prey-capturing
and killing mechanism. In this manner, and through prolon-
gation of the head region into a long flexible annulated pro-
boscis, the terminal raptorial claw of ^the free-swimming
Opabinia can be derived (Fig. 3B; Bousfield & Collins, in
preparation). The paired spines on each side are 14 in
number, as in Anomalocaris canadensis. The distal five of
these are longer and more steeply oblique and probably
served in prey capture, whereas the proximal nine pairs are
stouter, shorter, and more perpendicular and may have
served in holding, crushing, and possibly preliminary mas-
tication. The form and function of the claw is analogous to
a modern pair of pliers. However, it was probably activated
by a combination of muscular and hydrodynamic processes.
The transfer of food material rearwards to the mouth by the
proboscis was probably similar to the action of an elephant’s
flexible trunk. The proboscis does not contain the anterior
gut, as proposed by Sharov (1966) (per Callahan, 1979).
In a much more highly modified Upper Carboniferous,
internally segmented, squidlike counterpart, Tullimonstrum
gregarium, described in detail by Johnson & Richardson,
1969 (Fig. 7C.2), the terminal claw was more slender, and
the spines, 13- 14 in number on each side, were minute (Fig.
3C). Prey items were probably small and soft-bodied,
possibly free-swimming plankters, or worms or insect larvae
extracted from tubes in soft bottom sediments.
In a Lower Cambrian benthic species, Cassubia infra-
cambriensis (Lendzion, 1975), the number of pre-oral limb
segments was reduced to 7, and segments 2-5 had large
medial spinose processes (Fig. 3E). Regrettably, the plane
of motion is not precisely determinable from the single in-
complete fossil specimen.
In a direction presumably leading to the chelicerates,
the pre-oral appendage of the protochelicerates Jianfengia
and Yohoia was reduced to 3-4 segments, the outermost
being double-spined and movably pincering upon the inner
marginal spine of segment 2 (Fig. 3F). Limb orientation was
in a vertical plane and the movable distal spine had been
AMPHIPACIFICA VOL. 11. NO. 1 AUG. 31, 1995 12
FIG. 3. PLAUSIBLE EVOLUTIONARY SCENARIOS IN THE PRE-ORAL APPENDAGE
OF UNIANTENNATE ARTHROPODS (from Gould (1989) and various sources)
A. D. Anomalocaris spp. ( Hypothetical Ancestrai type)
Raptorial proboscoid line B. Opabima C. Tullimomtrum (Carboniferous)
Raptorial chelicerate line £. Cassubia F. Yohoia tenuis Gl. Limulus (late Palaeo 2 oic)
Sensory flagellar line H. LeanchoiUa J. Actaeus K. Emeraldella
rotated to the lower or inner side, as in limuloids and phal-
angiate arachnids (Fig. 3G1). In eurypterids, scorpions, and
pedipalpate arachnids (including spiders), however, the move-
able segment is on the upper or outer side of the limb (Fig.
3G2). A major link in the presumed lineage from Yohoia to
merostomatid arachnids is not confirmed from the fossil
record, viz., a yohoiid-like pre-oral appendage on a broad-
ened head of 5 post-oral segments.
A further evolutionary thrust of the pre-oral uniantennate
limb resulted in a filamentous sensory flagellum, repre-
sented in early stages by the form of the 7-segmented "great
appendage" of LeanchoiUa (Fig. 3H). The inner marginal
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 13
FIG. 4. PROPOSED HOMOLOGIES BETWEEN PRE-ORAL APPENDAGES OF MIDDLE CAMBRIAN
TRILOBrrOMORPH UNIANTENN AXES AND ANTENNULES OF CRUSTACEAN fCIRRIPEDE AND
ASCOTHORACID) BIANTENNATE ARTHROPODS (A,B,C after Gould, 1989 ; D, E, F after Schram, 1986)
spines of segments 3-4 and the terminal spine of segment 7
were apparently modified as a multi-segmented whip-like
flagellum, whereas those of segments 5 and 6 were reduced
to short stubs. In Actaeus (Fig. 7E.3), segments 3 and 4
remained flagellated, but 5-7 were much shortened, and bore
short spine-like processes. In Sanctacaris, segment 3 (?) was
short-flagellate and (4?) 5-7 terminated in a star-hke cluster
of spines (Fig. 4C; 6D). Derivation of a 3-segmented
chelicera from such an appendage would seem improbable.
The simple elongate flagellar state is attained in Alalcomeneus
(Fig. 7E.4), Emeraldella (Fig. 3K) and in most other
trilobitoids, including the Burgessiida and the Trilobita
(Fig. 5E, F).
This analysis concludes that, in some evolutionary lines
within uniantennate arthropods, the pre-oral appendage was
initially a raptorial food gathering apparatus that secondarily
became flagelliform. These morphotypes, including the
trilobites, did not persist beyond the Paleozoic Era. In the
evolution of primitive merostomes (e.g. Chasmataspis), a
filiform antenna is unlikely to have disappeared, and a
cheliform appendage suddenly appeared, as Bergstrom (1979)
proposed for early chelicerates. The pre-oral appendage was
already semi-cheliform in the proposed ancestral Yohoia.
The trend from raptorial to sensory flagellar condition within
the Trilobitoidea, rather than the reverse, is accompanied by
parallel evolutionary trends in cephahzation of the head,
gnathobasic development of ambulatory limbs, rearward
shift of respiratory limbs, and in other major character states
within component major sub-taxa (p. 22).
Within biantennate arthropods, however, the evolution-
ary picture is different. As revealed by the limited early fossil
record, and the ontogeny of larval stages of extant and fossil
forms, the pre-oral appendage appears to been filiform
thoughout, with few exceptions, as noted on page 14). The
flagellate form has also persisted, with little change, in the
myriapod and hexapod taxa that have dominated terrestrial
environments since the close of the Paleozoic Era (Delle
Cave & Simonetta, 1991).
Possible Homologies in Pre-oral Appendages of
Uniantennate and Biantennate Arthropods.
As noted above, the significance of the first pre-oral
appendage as a mechanism of food detection, food gathering,
and general feeding style is basic in the Arthropoda. Both
the organelles of the acron (e. g., frontal filaments, naupliar
eyes) and the pre-oral first segmented head appendage are
presumed sensors of environmental conditions and food
sources. In uniantennates, the primary role ofthe latter was
food gathering, a raptorial function that was retained in the
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 14
single successful line of uniantennate evolution, the
Chelicerata. In the biantennates, however, the appendage
was primarily sensory, at an early stage, and remained so
throughout evolutionary history of all major subgroups. A
comparison of pre-oral limbs of selected primitive morpho-
types of both uni- and bi-antennates is pertinent (Fig. 4).
In the primitive trilobitomorphs, the pre-oral appendage
passes through several stages of reduction of accessory
flagella and sensory organelles (Figs. 4A, B, C). leading to
the simple elongate flagellar condition of the Trilobita and
Emeraldellida. In a few primitive maxillopodan crustaceans
with specialized life styles, however, the appendages devel-
oped correspondingly specialized sensory and raptorial func-
tions. In cirripedes, the antennules are natatory in naupliar
and metanaupliar larvae (Fig. 4D), but become organs of site
selection and attachment in the cyprid larvae of sessile, shell-
burrowing and parasitic forms, the Thoracica, Acrothoracica,
and Rhizocephalia respectively (Glenner&Hoeg, 1995)(Fig.
4E). These 4-segmented antennules bear aperhaps superficial
but remarkable similarity, and almost certainly homologous
relationship to, the pre-oral appendage of the primitive
trilobitoiduniantennates, (Fig. 4B), andSanctacaris
(Fig. 4C).
However, in the ascothoracidan biantennates, parasitic
on echinoderm and anthozoan coelenterates, the antennule
is raptorial in the cyprid and adult stages (Fig. 4F). The term-
inal two segments of the 4-segmented appendage, reminis-
cent of Yohoia (Fig. 3F), form a subchela for attachment to
the host, or removal of pieces of the host tissue as food.
Perhaps a more precise concept of the pre-oral append-
ages of long extinct uniantennates of the Cambrian Period
might be derived through closer study of the antennules of
these very primitive extant crustacean biantennates.
The Pre-oral Appendage of Trilobitoid Uniantennates,
The general external morphology of selected tiilob-
itomorph uniantennates is shown in Fig. 5. In Burgessia
(Fig. 5 A), Molaria (Fig. 5B) andHabelia (Fig. 5C), the head
comprises four segments (five somites) which, in Burgessia,
subtends a broad carapace covering the trunk segments. The
post-oral appendages are ambulatory, those of the trunk also
respiratory. The trunk terminates in a spikelike telson,
similar to that of the merostomatid chelicerates, and suggests
a strongly benthic life style. In Sidneyia (Fig. 5D), the head
is only 2-segmented, but the anterior four trunk segments
bear uniramous, powerfully gnathobasic limbs that are effec-
tively part of the cephalic masticatory complex. The
posterior 3 trunk segments are free and bear a broad, flabellate
telson, evidence that Sidneyia was a powerfully swimming
benthic and epibenthic predator.
In the trilobites, [e.g., Naraoia , a "soft trilobite" (Fig.
5E), and Olenoides, a primitive true trilobite (Fig. 5F)], the
head is also 4- segmented, with 3 pairs of post-oral ambula-
tory, respiratory, and masticatory head limbs, and 11+ pairs
of similar trunk limbs. However, trilobites differ from Bur-
gessiida in having a broad depressed head shield and trunk,
the latter ending in a short pygidium or tail region of a
variable number of segments. Both groups represent middle
stages in cephalization of anterior trunk limbs.
Sanctacaris
On the basis of five well-preserved specimens from the
Stephen Formation, near to but slightly younger than the
Burgess Shale quarry, Briggs and Collins (1988) described
a large carnivorous arthropod, Sanctacaris uncata, that they
assigned to subphylum Chelicerata (Fig. 6). The broad head
bears large eyes and six pairs of biramous appendages, the
first five of which form a raptorial array of segmented,
spinose and gnathobasic endopods with simple short
antennalike exopods. The outer ramus of the sixth limb is
also filamentous, but the inner ramus is short, terminating in
a firinge of starlike radiating spines. The mouth is located
anteriorly, presumably in a narrow gap between the first limb
bases. The broad trunk is 11 -segmented, the posterior
bearing a paddle-shaped telson, the anterior 10 each bearing
paired biramous lim bs of which the exopod is large, flabellate,
and natatory-respiratory in function. The inner ramus is
slender, multi-segmented, and presumably ambulatory;
marginal spines and/or gnathobases were not demonstrable.
However, another interpretation is utilized here. The
biramous "sixth" appendage (Fig. 6D), bears a striking
resemblance to the "transitional" pre-oral limb of Actaeus,
with its star-shaped accessory flagellum (Fig. 5B), but unlike
the raptorial condition in Yohoiida (Fig. 3F; 7D) or the
chelicerate condition in arachnids (Fig. 6F). Furthermore it
arises near the eye, in a typically pre-oral position. The five
pairs of raptorial head limbs of Sanctacaris have apparently
been displaced forward beneath the head to form a raptorial
"basket", immediately beneath the mouth. These limbs,
although non-ambulatory, appear to be homologous with the
five pairs of post-oral head limbs of Emeraldella (Fig. 6E).
The latter has a single filamentous pre-oral flagellum that is
apparently homologous with the short biramous "antenna"
of Sanctacaris, In Emeraldella also, the post-oral head
limbs are similar to the trunk limbs in being strongly ambu-
latory as well as gnathobasic.
On this interpretation, and in agreement with Delle Cave
& Simonetta (1991), Sanctacaris is removed from the Chel-
icerata and placed in Class Emeraldellacea within the revised
superclass Trilobitoidea (Table ni,p. 24). Sanctacaris thus
stands as a unique, relatively advanced, but apparently short-
lived, sideline of Cambrian uniantennate evolution.
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 15
FIG. 5. CAMBRIAN ARTHROPODS: WITH GNATHOBASIC LIMBS AND FILAMENTOUS
PRE-ORAL APPENDAGES (variously from Gould (1989) and Briggs et al (1993)
Evolutionary Pathways in Uniantennate Arthropods
Plausible evolutionary pathways within uniantennate
arthropods of the Cambrian period that led to more highly
evolved trilobitoid and chelicerate faunas of the middle and
late Paleozoic are summarized in Fig. 7 (p. 17). The chart
embodies information provided in Table I, and figures 2, 3,
5 & 6 especially. The degree of morphological evolution
and specialization of feeding style is represented by four
blocks or zones, proceeding along the X-axis, from the most
primitive (pharyngeal feeding) on the left, through a narrow
transitional band in the middle, to limb gnathobasic and limb
masticatory feeding types on the right. Of these, the chelic-
erate form on the extreme upper right is the most advanced.
The Y-axis represents a generalized, rather than definitive,
time scale.
As noted previously, the most primitive and presumably
ancestral uniantennate arthropod of the late Precambrian,
Vendian, and Early Cambrian Periods was a member of the
predatory and pharyngeal-feeding Anomalocarida, illus-
trated on the lower left. These large-eyed animals possessed
a short head (2-4 somites), and a multisegmented body with
bilobate lateral pleurae or biramous ambulatory and
respiratory paired appendages. In a cephalopodlike feeding
AMPHIPACIFICA VOL. D. NO. 1 AUG. 31, 1995
16
FIG. 6. EXTERNAL MORPHOLOGY OF SANCTACARIS (modified from Briggs & Collins, 1988)
A. Life-like Reconstruction. B. Dorsal View. C. Head region (MAG. X), D. Pre-oral appendage (X)
E. (Inset). Head appendages of Emeraldella (ventral view)
F. L/mu/us Left chelicera G. Cassubia Left Pre-oral Appendage.
style, paired raptorial pre-oral head appendages apparently
captured and transported food to the mouth region where it
was masticated and ingested without post-oral limb assist-
ance. Within the Anomalocarida per se . development of a
benthic life style was accompanied by reduced segmentation
but stronger armature, possibly partly fossorial in function,
of the pre-oral raptorial limbs (e.g., 'm"Laggania" - type
fossils (Table I) and in Cassubia Lendzion, 1977, centre
line).
Of the three proposed evolutionary offshots from the
Anomalocarida, the epibenthic probosciferidans (on the left)
developed a very specialized food capturing mechanism,
similar in function to the hetercotyl arms of cephalopods, but
found nowhere else among the arthropods. It consisted of
horizontally opposing limbs fused together in a claw-like
appendage that was activated by a flexible proboscoid ex-
tension of the anterior head region. Its movements were pre-
sumably triangulated and co-ordinated by widely set pairs of
stalked compound eyes. The small size of this "proboscis",
and lack of peribuccal or pharyngeal teeth, indicate that the
prey organisms were very probably small and soft-bodied.
Cladistic presentation of relationships of Tullimonst-
rum by Beall (1991 ) may be a case of "bending the facts" to
fit theoretical models. None of his cladograms provides
close relationships between Tullimonstrum and other major
invertebrate groups, and each cladogram contradicts rel-
ationships depicted by the others. The "re-interpreted" ani-
mal appears unfunctional (e. g., a vertical tail on a depressed
trunk) and inconsistent with the taxonomic details of Rich-
ardson (1966) and Johnson & Richardson ( 1969) that resulted
AMPHIPACIFICA VOL. n. NO. 1 AUG. 31, 1995 17
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no. 7. RELATIONSHIPS OF CAMBRUN UNIANTENNATE ATHROPODS
BASED ON FEEDING MECHANISMS
AMPHIPACIFICA VOL. n. NO. 1 AUG. 31, 1995 18
from careful observations on numerous specimens.
A more successful evolutionary experiment typifies the
mostly benthic trilobitoid line to the right. In it, the pre-oral
limb lost its raptorial function and became flagelliform,
multi-segmented, and presumably mainly sensory and perhaps
tactile in function. Simultaneously, the post-oral head and
trunk limbs developed a linear gnathobasic endopod which,
through various degrees of cephalization of anterior trunk
segments, formed a masticatory feeding field of 2-5 pairs of
post-oral head appendages. Remarkably, the species of
Leanchoiliidea (including Acanthomeridion from Chengjiang
deposits) sit squarely in the transitional zone of both pre- and
post-oral limb evolution. Alalcomenaeus, having the most
advanced, mono-filamentous pre-oral appendage, also has
nearly fully gnathobasic post-oral appendages (Delle Cave
& Simonetta, 1991).
Of the flagellated trilobitoids with 3 post-oral head
segments, the "spike-telsonic" group (centre right) encom-
passed the Habelia subgroup having armoured processiferous
bodies and short antenna. The associated Molaria, also
having filamentous antenna and only three post-oral head
segments, is an unlikely precursors of the chelicerates, as
proposed by Delle Cave and Simonetta (1991, Chart II).
Trilobitoideans withpygidial (non telsonic) abdomens (lower
right) included narrow-bodied "idotheid" or "asellid" isopod-
like forms such as Mollisonia and Urokodia that may have
occupied algal substrates. They also included broad, flat-
bodied, fossorial types with protective exoskeletal armour,
leading to their only successful subgroup, the trilobites, that
di versed in the later Paleozoic times.
The trilobitoids include the Eraeraldellidacea that have
5 post-oral head segments and a spike-like telson (upper
right). The group here includes the aglaspids, thought to
possess chelicerae prior to the work of Briggs et al (1978).
Aglaspids "straddle" the Upper Cambrian- Lower Ordovician
boundary. The Devonian Cheloniellon may be a distant
descendent of the main line of Emeraldellidea. As mentioned
above, a carnivorous form with paddle-like telson, Sancta-
caris, is considered an early offshoot of this same line. This
species has 5 distinct post-oral head segments, each with bi-
ramous paired raptorial limbs. Sidneyia has no post-oral
head limbs but the first four trunk limbs are uniramous
(lacking gills), strongly gnathobasic and form, effectively, a
post-oral masticatory field of four segments. Sidneyia is here
regarded as a very early (relict) stage of cephalization of ant-
erior trunk appendages, and had a separate origin (Fig. 7K).
The most successful anomalocarid offshoot is here
believed to be the Jianfengia- Yohoia line, to the upper right
of Fig. 7. The post-oral head limbs, in the process of losing
respiratory exopods, were already ambulatory and transitional
in form. Although the pre-oral head limbs remained rapto-
rial, their reduced size and segmentation and subcheliform
appearance are plausible precursors to the fully chelicerate
condition found in the most primitive arachnids, the mero-
stomes, of the Lower Ordovician (upper right). However,
the viability of this proposed evolutionary connection awaits
discovery of a broadly flat-bodied fossil having transitional
masticatory post-oral head and trunk limbs and a more
clearly cheliform (rather than geniculate) pre-oral append-
age. Triopus (Fig. 7P.1) may approach that predicted form
but its appendages are poorly known. Chasmataspis (Fig.
7P2) is the most primitive Lower Ordovician undoubted
chelicerate, leading to the eurypterids. Although not
completely understood (Bergstrom, 1979), Chasmataspis
has 5 post-oral head segments and 12 trunk segments. The
total is one more than the combined number of post-oral
segments of the presumed ancestral Yohoia.
The Euthycarcinoidea Enigma
The enigmatic group of aquatic arthropods classified as
Euthycarcinoidea, is based on a half-dozen limnic (?) species
that existed from Carboniferous to Triassic time. Bergstrom
(1979) summarized information on theTriassic generaEwr/iy-
carcinus and Synaustrus, and Schram and Emerson (1991)
utilized the upper Carboniferous genera Pieckoxerxes and
Kottixerxes in developing their newly proposed Arthropod
Pattern Theory (Fig. 8). The broad head shield is typically
composed of 3 somites including an eye-bearing acron, an
anterior procephalon with a single pair of filamentous anten-
nae, and a posterior gnathocephalon bearing a set of mandi-
ble-like appendages and on which the mouth opens ventrally .
The broadened trunk is divided into an anterior (thoracic)
region of diplo- or triplo- segments each bearing paired
uniramous limbs, and a posterior narrower and limbless
abdomen that terminates in a spikelike telson.
According to Schram & Emerson (loc. cit.), the possession
of uniramous limbs and diplosegments may link these animals
to the ancestry of the terrestrial myriapods and hexapods
(Uniramia of Manton, 1972). On the other hand, the overall
appearance of euthycarcinoideans is grossly similar to some
uniantennate arthropods having 3-6 head segments, and
filamentous pre-oral limbs, e.g., Leanchoilia, Habelia, and
Emeraldella. However, unlike the uniantennates, the trunk
endopods are filamentous, multisegmented, and lack rapto-
rial spines, gnathobases, and/or terminal claws. The leg seg-
ments bear slender posterior marginal spines that are possi-
bly of both natatory and respiratory support function, and in
that respect resemble the exopods of some uniantennate
arthropods (e.g., of Trilobitoidea).
The Lower Cambrian Chengjiang fossil deposits in
Yunnan region, South China, discovered in 1984, contain a
number of very primitive arthropods yet imperfectly known,
and mostly not included here. However, one of these,
Fuxianhuia protensa Hou, 1987b, is remarkably similar in
overall form to the euthycarcinoideans (above, and figs. 8A,
9) as detailed recently by Chen et al. (1995) (Fig. 8 A-H). The
body consists of a short, broad, head shield and an elongate
trunk region. The latter is divided into a thorax of 17 broad,
depressed, limb-bearing segments, and an abdomen of 14
narrower and more cylindrical, legless segments, the last
bearing a prominent telson spine. The head bears an anterior
pair of large stalked eyes, a pair of filamentous pre-oral
appendages (antennules) on somite 2 and, ventrally on
AMPHIPACIFICA VOL. U. NO. 1 AUG. 31. 1995 19
anteroveniral eye-bearing
plate ederite
FIG. 8. EUTHYCARCINOIDEA: Fuxianhuia protensa Hou, 1987 (Middle Cambrian)
A. Dorsal reconstruction Head shield B., C. ventral reconstr. D. dorsal reconstr.
E. Sutehelate head appendage F. Abdomen, ventral G. Abdomen (ventral X. 1987;
showily limbs) H. Pieckoxerxes piekoae K. Kottixerxes glotiosus (A. B - after Hou.
D-G (after Chen et al, 1995) H, L. (after Schram & Emerson, 1991).
J, K, Euthycarcinus Aerr/m (after Bergstrdm, 1979),
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 20
somite 3, a pair of subchelate raptorial limbs, presumably
arising on either of side of the mouth. These superficially
resemble the raptorial head limbs of the uniantennate arthro-
pod Cheloniellon, the raptorial maxillae of remipede crus-
taceans, and the raptorial first thoracic limbs of belostomatid
hemipteran insects. However, they are unlike the paired
palpless mandiblelike structure of the mouth region ascribed
to a few specimens of Euthycarcinus (Bergstrom, 1979).
In other details, however, the similarity of Fuxianhuia
to euthycarcinoideans is remarkably close. The trunk limbs
are biramous, with thin plate-like exopods, but the endopods
are cylindrical, multisegmented, and lack terminal claws.
These endopods are also similar to the multisegmented,
basally shafted rami of larval skaracarids of the Cambrian
"Orsten" fauna (Fig. 9, part). The limbless abdomen is found
elsewhere in most maxillopodan crustaceans (e.g., several
Skaracarida, Cirripedia, Copepoda, etc., and the
Cephalocarida) as well as some phyllocaridans and phyllopod
biantennates. The incomplete basal fusion of the trunk
exopods and endopods is reminiscent of the lateral lobe-like
paired flaps or limbs of the primitive dicephalosomatid
uniantennates. Modem aquatic predators with "jacknife"
raptorial limbs (above) are all free-swimming pelagic preda-
tors, perhaps indicating a similar life style in euthycarcinids.
In summary, Fuxianhuia bears some similarity to nearly
every major group of arthropods of the Lower and Middle
Cambrian Period but does not conform completely with any .
In the very primitive structure of his head and locomotory
limbs, and multi- segmented body, it is close to a model
arthropod ancestral type (e.g., of Snodgrass, 1956). How-
ever, the presence of two pairs of pre-oral head limbs, the
first of which is filamentous and the second raptorial, is
similar to the situation in crustaceans and some phyllocaridans,
and thus essentially biantennate. This feature, along with the
multisegmented, elawless endopods of the thoracic region,
justify its inclusion within the class Euthycarcinoidea. Its
other members are of more recent geological age, but
sufficiently distinct to justify erection of the primitive sub-
class Fuxianhuiacea (Table IV, p. 27).
Evolutionary Relationships in Aquatic Biantennates
A recapitulation of plausible evolutionary pathways
within early aquatic biantennate arthropods is sketched in
Fig. 9. On the left of the chart are connectives for two genera
of skaracarid crustacean larval forms, a phosphotocopine
ostracod, and a thecostracan cyprid, that represent the primi-
tive evolutionary phases of skaracarid, ostracod and
cirripedian maxillopodans of Cambrian times. Their primi-
tive character states included the shaftlike form of the basal
portion of the post-oral head limb endopods, the unbossed
condition of their ramal spines and setae, and the multi-
segmented rami that are found variously in early naupliar
stages of Copepoda, Cirripedia, and other extant maxillopod-
an crustacean subgroups. The systematics and evolutionary
history of maxillopodan crustaceans are relatively well known
(e.g., in Schram, 1986), and are not discussed further here.
In the centre are the euthycarcinoideans of which
Fuxianhuia from the Lower Cambrian is here designated the
the most primitive member. The Upper Carboniferous and
Triassic members are shorter-bodied, with diplo- and triplo-
trunk segments, uniramus limbs, and may be ancestral to
groups with the Myriapoda. However, further evidence from
Silurian and Devonian representatives is needed to clarify
such a phylogeny.
To the centre right are connectives between the three
subclasses of biantennates recognized here within a revised
and restricted definition of Latreille's original crustacean
class Phyllopoda (p. 26). These Cambrian groups resemble
extant branchiopodan and leptostracan crustaceans, at least
superficially, and may have had a late Precambiian or
Vendian common ancestor. The branchiocarids and
odaraiatids were regarded as unique arthropods and/or crus-
taceans by Briggs (1976, 1981). However, they differ from
true crustaceans in the 3- segmented head structure (lack of
clearly defined maxillae and maxillary segments) and the
carapace is mandibular rather than maxillary in origin.
Although Schram (1986), following Briggs (1978), assigned
the Canadaspida to Malacostracan subclass Phyllocarida,
Dahl (1984, 1987) convincingly demonstrated primary dif-
ferences of tagmatization, total number of body segments,
position and form of the presumed mandible, limb structure
and other anomalous features that, under existing defini-
tions, remove the Canadaspida from the Phyllocarida, and
the true Crustacea.
In Fig. 9, lower right, are the marrellomorphs. These
represent one of the few aquatic biantennate arthropods with
qualifications for direct ancestry to the myriapods and hexa-
pods, its leg features postulated by Kukalova-Peck (1992).
Thus, marrellomorphs are biantennate and the head limbs
possibly mandibulate, but not ambulatory-gnathobasic. They
are mainly benthic in life style and the anterior limbs are
apparently double-clawed, suited to walking or crawling
over firm substrates. They also possess similar body
tagmatization and limb structure, and the telson is minute or
lacking. The leglike maxillary and labial palps of
an Upper Carboniferous monuran wingless insect (Fig. 9)
are remarkably similar in form to the endopods of the
ambulatory head limbs of the Devonian marrellomorphs
Mimetaster and Vachonisia (Stiirmer & Bergstrom, 1976).
Loss of the second head segment and its antennalike pre-oral
limbs in myriapods and hexapods accords with overall
evolutionary trend to reduction of limbs and accessory lobes
that accompany a shift from aquatic to terrestrial life style.
In air, gravitational effects on limb structure are more signifi-
cant; two pairs of sensory limbs would thus appear to be
mechanically unwieldy and functionally unnecessary.
Phylogenetic Tree of the Arthropoda
An annotated classification of uniantennate and
biantennate arthropods is presented in Tables III (p. 25) and
IV (p. 27) respectively, the number of higher categories of
which are summarized in Table V (p. 29). Hypothetical
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 21
FIG. 9. PHYLETIC LINKAGES WITHIN BI ANTENNATE ARTHROPODS S 2
OF THE PALEOZOIC ERA
relationships of the major genera of the Cambrian Period to
each other and to other major groups of arthropods over the
600+ million year geological and evolutionary time scale are
summarized in the accompanying chart (Fig. 10, p. 23).
Phyletic relationships may be presented in a number of
graphical ways, including cladograms (e.g. Briggs & Fortey
1989), following an earlier attempt by Briggs (1983). Those
authors (1989) utilized 26 characters and corresponding
character states in deriving an arrangement in which the
biantennate branchiopods clustered near the base, the
trilobites at the advanced end, and various trilobitoideans
and arachnids at intermediate levels of the evolutionary
AMPHIPACMCA VOL. 11. NO. 1 AUG. 31, 1995 22
scale. Whereas this scheme has an overall plausibility, it is
limited in detail by the omission of dicephalosomatid arthro-
pods or other related outgroup taxon, by other possibilities in
the ordering of some character states, and by weaknesses
inherent in cladistic analyses generally (see Gosliner and
Ghiseln, 1984).
In view of limitations of cladistic methodology at this
stage of knowledge, the writer finds merit in modifications
of the simple phyletic tree arrangements of Delle Cave &
Simonetta (1991), for various early arthropod subgroups, as
outlined here in Fig. 10. The hypothetical " tree" com-
mences somewhere within late Precambrian times, in con-
formity with the views of Dzik & Knimbiegel (1989). Thus,
representatives of tardigrade and onychophoran pararthropods
and both uniantennate and biantennate arthropods were
already present in the earliest (Lower Cambrian) fossil
deposits (Dzik &Lendzion, 1988). Also, protarthropods (e.g
Xenusia) and some antennognath arthropods (e.g., Spriggina,
Praecambridium) are also known from Ediacrian and V end-
ian fossil deposits (Delle Cave & Simonetta, 1991).
The earliest and morphologically most primitive
uniantennulate subgroup of Cambrian times is here consid-
ered to be the dicephalosomatids (p. 25). The primitive ano-
malocarids did not suri ve the Cambrian and the more advanced
probosciferans lasted only until the Upper Carboniferous.
The Yohoiida, possibly on a direct ancestral line with the
chelicerates, also became extinct in the Cambrian. Not yet
discovered, however, is a theoretical Cambrian fossil form
having a 6-segmented head, transitional post-oral mastica-
tory limbs, and fully cheliceriform pre-oral appendages that
might directly link the group with the chasmataspids and
primitive aquatic arachnids of Ordovician and later periods.
Of the aquatic merostomes, the eurypterids diversified dur-
ing the mid Paleozoic but became extinct prior to the
Mesozoic, and few relict limulids are the only modem
survivors of those primitive aquatic chelicerates.
The Trilobitoidea embodied various combinations of
head and trunk segments having filiform, sensory pre-oral
appendages and raptorial, gnathobasic, post-oral feeding
and ambulatory limbs. Several of these, including early
trilobites (e.g., olenellids) apparently became extinct during
the Cambrian, although the Emeraldellidea persisted until
the Devonian (e.g., Chelionellon). The more advanced
trilobites became the single most speciose and diverse group
of aquatic uniantennates during the early Paleozoic. They
apparently survived longer than any other other arthropod
group having only 4 head segments, but were gone by the
beginning of the Mesozoic.
The paleohistory of the biantennates is less clear. Prim-
itive biantennates, the euthycarcinoids, marrellomorphs and
phyllopods occurred, even abundantly, in the Cambrian.
However, the inarrellomophs survived only until the Upper
Paleozoic, and the euthycarcinoids to the Triassic. As noted
on page 1 8, the marrellomorphs provide a plausible (but not
confirmed) aquatic ancestor to the terrestrial myriapods and
hexapods whose fossil records commenced in the lower
Devonian and upper Silurian periods. Kukalova-Peck (1992)
has provided convincing evidence that the myriapod and
hexapods could not have originated from the Xenusian-
onycophoran line of "uniramians", a conclusion supported
by the present study.
The fossil record of early cmstaceans is uneven, but
little doubt exists, especially as result of remarkable new
micro-fossils in the Swedish ’Orsten’ deposits, revealed by
Walossek & Muller (1989), that the maxillopodans were a
very diverse biantennate group by Middle and Upper Cam-
brian times. Maxillopodans continued to exploit aquatic
niches and food resources in which small size, free-swim-
ming metamorphic developmental stages, and filter-feeding
mechanisms are advantageous. The somewhat larger
Branchiopoda, by developing a resting egg stage, have
managed to survive, mainly in temporary freshwater habi-
tats, over a comparable time frame. Their non-palpar
mandible, even in early naupliar stages (Sanders, 1963), may
indicate an early link with the Phyllopoda. There is little
basis for a direct phyletic link with the trilobitoideans, as
studied by Hessler & Newman (1975).
With respect to the Cephalocarida and the Remipedia,
crustacean classes discovered only during the later half of
this century, their body and limb structures are more primitive
than most other maxillopodans, and certainly the malacost-
. racans (Schram, 1986). Despite their problematical late
Paleozoic (or non-existant) fossil records, an early Paleozoic
origin for both groups is a reasonable expectation.
The Malacostraca may be considered the dominant and
most diverse crustacean class of Recent times (Bousfield &
Conlan, 1990). Transfer of the orders Canadaspida and
Branchiocarida from the Crustacea to the phyllopod Bi-
antennata (p. 25), leaves the Upper Devonian protoglyphaeid
reptantian Palaeopalaemon newberryi as the earliest con-
firmed malaeostracan fossil record (Schram, 1986). How-
ever, the relatively plesiomorphic body segmentation and
limb structure of the Leptostraca (sensu strictu), as well as
the Hoplocarida and Syncarida, would suggest a somewhat
earlier beginning for the malacostracans, possibly during the
Silurian or late Ordovician.
THE CAMBRIAN ARTHROPOD FAUNA: EVOLU-
TIONARY TRENDS,
Early trends in the direction of morphological and be-
havioural evolution in arthropods, revealed by Burgess Shale
and other Cambrian faunal assemblages, are summarized as
follows:
(1) Within uniantennate arthropods, the ancestral pharyn-
geal and peribuccal feeding methodology was replaced by a
masticatory assemblage of post-oral gnathobasic limbs of
the head region. The taxonomic series of Anomalocaris,
Leanchoilia and Emeraldella represents this transformat-
ional process.
(2) Also within the uniantennates, the primitively large
raptorial food-gathering limbs of the pre-oral head region
gave rise to short, paired cheliform and chiefly masticatory
appendages within the higher (terrestrial) Chelicerata. The
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 23
-LOG T 1
M E
LO
o
LO
CO
o
CM
to
u>
SCALE
(M. Y. B. P.)
o
c.|mesoz
FIG. 10.
U. PAL. L. PAL CAMBRIAN
PHYLOGENETIC TREE OF THE ARTHROPODA
PRECAMBR.
no. 10. PHYLOGENETIC TREE OF THE ARTHROPODA. EMPHASIZING THE MIDDLE CAMBRIAN FAUNA
(Based parti}' «■ Schram (1986) and Boosfield & Coalan (1990)
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 24
taxonomic sequence of Artoma/ocam, Yohoia, Chasmataspis,
and the Scorpionida illustrates this evolutionary sequence.
(3) Other types of pre-oral limb development that involved
an opposing limb raptorial mechanism on the one hand, and
a filamentous sensory structure on the other, did not survive
the close of the Paleozoic Era.
(4) The cephalization, or incorporation of masticatory limbs
of anterior trunk segments into the head shield, of both uni-
and bi-antennate arthropods, proceeded most rapidly during
the Cambrian Period. Such a rapid evolutionary process in
major taxonomic features may prove to be a direct example
of punctuated equilibrium proposed by Eldridge & Gould
(1972). However, few aquatic taxa with only 2-4 head
somites (e.g., a few Probosciferida, Marrellomorpha) sur-
vived beyond the Cambrian, although the euthycarcinoids
persisted until the Triassic; some with five somites (e.g.,
Trilobita) reached the late Paleozoic; whereas groups with 6-
7 head somites (e.g. Crustacea, Chelicerata) extended into
Mesozoic and Recent times.
(5) Primitively shaftlike and elongate trunk limbs became
increasingly distinctly segmented, chitinized, and shortened,
especially in benthic forms. A series of forms within the
crustacean order Skaracarida (e.g. Data, Bredocaris, and
Oleandocaris), the phosphatocopine ostracods, and the
naupliar-metanaupliar stages of other maxillopodan
crustaceans, illustrate such transformation.
(6) The dorsal shield arises from the first head segment (pre-
oral carapace) in primitive, pharyngeal -feeding arthropods.
In more advanced, limb-masticatory arthropods (e.g., mandib-
ulates) the carapace (secondarily bivalved) arises from the
posterior segment of the head shield that is mandibular in
phyllopods and typically maxillary in crustaceans.
(7) With respect to the natatory function of limbs, swimming
appendages occur in both post-oral head and trunkregions of
very early uniantennates, and larval stages of more advanced
arthropods. Coincident with tagmatization of the trunk into
thorax and abdomen, and the "cephalization" of feeding
limbs in higher taxa, swimming, and respiratory, functions
shifted posteriorly from head to thorax and finally to abdo-
men, as in stomatopods, isopods, and other Malacostraca.
(8) Evolution of the terrestrial myriapods and hexapods from
presumed aquatic ancestors apparently involved loss of the
second pre-oral head segment and its antennate appendages.
In the aquatic environment, those limbs are functionally
sensory (see Callahan, 1979), locomotory, or even food
gathering. In the terrestrial environment, such limbs
presumably became duplicative and mechanically unwieldy,
and followed into oblivion the original prothoracic wings of
insects. Similarly, in peracaridan crustaceans that have
become secondarily terrestrial (e.g., talitrid amphipods,
oniscoidean isopods), one of the sensory antennal pairs (first,
antennules) has become very much reduced or vestigial, with
only one pair (second, antennal) remaining effectively
functional. In similar vein, an alternative functional evolution
of the head appendages of myriapods and hexapods would
countenance die fusion of the first pre-oral limbs to the
labrum to form the clypeo-lahrum, and the second pair of
head appendages, equivalent to the second antennae of
crustaceans, have become the monofilamentous antennae of
the hexapods. However, embryological and/or paleohistorical
(fossil) evidence for such a proposal has not yet been
demonstrated.
In summary, in the most successful arthropod groups of
modem times, the head shield encompasses anterior limbs of
the primordial tmnk region, limbs that assist in food capture
and mastication. Body tagmatization has become pro-
nounced, and swimming, ambulatory and respiratory func-
tions are relegated increasingly to thoracic and abdominal
limbs (see also Schram, 1986). In higher cmstaceans
(malacostracans), thoracic limbs have become uniramous,
cheliform and versatile, and the antennules secondarily bi- or
tri-ramous and sensory. In higher arachnids, however (e.g. ,
pedipalpids and phalangids), the prosomal limb gnathobases
have become secondarily lost, but feeding mechanisms
remain primitive in the retention of chelicerate pre-oral
limbs and a suctorial pharynx. In tracheates, the exopods of
trunk limbs have been lost. In hexapods, the abdominal
limbs have become vestigial or lost entirely, and exites of
limbs have secondarily become gills and/or trachaeae in the
abdomen, and trachaeae and/or wings in the thorax (see
Kukalova-Peck, 1987,1 992). Such fundamental morpho-
logical changes in arthropod body form have unquestionably
contributed vitally to the ability of modem groups to utilize
the diverse organic and plant-related food resources that
have evolved mainly in terrestrial habitats, and mainly since
the late Paleozoic Era.
Source references for taxonomic andclassificatory names
and time-scale occurrences in following Tables III-V are:
E. L. Smith - unpublished MS "Atlas of Insect Morphology";
L. Stprmer (1959) - in Treatise on Invertebrate Paleontology ;
J Bergstrom (1979) - "Morphology of Fossil Arthropods"; S.
J. Gould (1989) - "Wonderful Life" & source materials;
D.E.G. Briggs et al. (1993) - "The Burgess Shale fauna" and
source material; L. Delle Cave & A. M. Simonetta (1991)-
"Early Palaeozoic Arthropods"; T. Savory (1964) - "Arach-
nids"; F. R. Schram (1986) - "Crustacea"; and numerous
other source papers inducting arthropod sections in "Synop-
sis and Classification of Living organisms", McGraw Hill,
1982.
A database for analysis of the paleohistorical occurence
of major taxonomic groups is given in Table V (p. 28). Some
taxonomic names, especially those relatively recently pub-
lished or not sufficiently well described (e.g., Wapria Walcott,
1912) have been omitted from the lists and the analysis. A
complete bibliography of citations of taxonomic names is
not included in the references here, but may be found in the
Zoological Record or other basic reference texts for the taxa,
author names and dates concerned.
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 25
TABLE ni. SUGGESTED NATURAL CLASSIFICATION OF AQUATIC, ESPECIALLY EARLY
PALEOZOIC, ARTHROPODA BASED ON FOOD-GATHERING AND FEEDING MECHANISMS.
PHYLUM ARTHROPODA
I. INFRAPHYLUM UNIANTENNATA, new name (= MANDIBULOPODA E. L. Smith ’Atlas ”)
One pair of positionally and embryonically pre-oral head limbs; trunk limbs often gnathobasic.
tSUPERCLASS DICEPHALOSOMATA Sharov, 1966 (L. Camb. - U. Carb)
Pre-oral limbs raptorial, non cheliform, 4-14 segments; post-oral limbs non food-gathering; feeding pharyn-
geal, assisted by pre-oral limbs; trunk 12+ segmented, pygidial?; limbs locomotory, respiratory; aquatic.
tCLASS ANOMALOCARIDEA Raymond, 1935 (L. - M. Camb.)
Pre-oral limbs paired, 7-14 segmented; 1-3 post-oral head segments; peribuccal teeth present.
tSUBCLASS ANOMALOCARIDATA new (L. - M. Camb)
Pre-oral limbs 1 1-14-segmented; 3 post-oral head segments; trunk limbs natatory
tOrder Anomalocarida Raymond, 1935 (Anomalocaris Whiteaves, 1892; ?Hurdia Walcott 19121
tSUBCLASS CASSUBIATA new (L. Camb)
Pre-oral limbs 7-segmented; 1? post-oral head segment; anterior trunk limbs ambulatory?
tOrder Cassubiida new {Cassubia Lendzion, 1977)
tCLASS PROTOCHELICERATA Strmer, 1944, revised and restricted (L. - M. Camb.)0
Pre-oral limbs paired, semi-chelicerate, 4-5 segmented; 3 pairs post-oral, biramous ambulatory head limbs.
tSUBCLASS YOHOIIDACEA Henriksen 1928, new status (L. - M. Camb)
Trunk limbs biramous, natatory, respiratory.
tSuperorder Yohoiidea Henriksen 1928
tOrder Jianfengiida new (Jianfengia Hou, 1987) (L. Camb)
tOrder Yohoiida Henriksen 1928 (Yohoia Walcott, 1912) (M. Camb)
tCLASS PROBOSCIFERIDEA Sharov, 1966 emend (M. Camb - U. Carb)
Pre-oral limbs fused to clawlike (14- segmented) jaws on anterior proboscis; post-oral head segments and
peribuccal teeth lacking.
tSUBCLASS OPABINIIDACEA Stprmer, 1944 (M. Camb)
tOrder Opabiniida St0nner, 1944 (Opabinia Walcott, 1912-, ?Kerygmachela Conway Morris etaK 1987)
tSUBCLASS TULLIMONSTRIDEA E. L. Smith "Atlas" (U. Carb)
tOrder TuUimonstrida (Tullimonstrum Richardson, 1966)
tSUPERCLASS TRILOBITOMORPHA Stprmer, 1944, restricted status (L. Camb. - M. Perm.)
Pre-oral limbs filamentous, non raptorial; post-oral head limbs and trunk limbs normally biramous,
endopods modified for food-gathering and/or feeding.
tCLASS (SUBCLASS) LEANCHOILIIDACEA Raymond, 1953, new status (L. - U. Camb.)
2-3 pairs post-oral, spinose (or weakly gnathobasic) transitional head limbs; trunk limb endopods
transitional; telson large.
tSuperorder Leanchofliidea Raymond, 1935
Head with 2 post-oral segments; pre-oral limbs multi-flagellate; eyes lacking.
tOrder LeanchoBuda (L^awc/wi/ia Walcott, \9\2\ Acanthomeridion Hou, Chen &Lu, 1989 )
tSuperorder Alalcomenaeidea Simonetta, 1970
Head with 3 post-oral segments; pre-oral limbs bi-flagellate or with accessory lobe; eyes present
tOrder Actaeida {Actaeus Simonetta, 1970)
tOrder Alalcomenaeida {Alalcomenaeus Simonetta, 1970;
tCLASS (SUBCLASS) SIDNEYIDEA Walcott, 1911, new status (M. Camb.)
Uc^ng post-oral head segment(s) or limbs; trunk not trilobate, limbs gnathobasic; telson flabellate
tOrder Limulavida Walcott, 1911. {Sidney ia^^\co% 1911) (S«rarmcerc«^ - a larval stage?)
tCLASS TRILOBITOIDEA Stprmer, 1955, restricted (L. Camb. - U. Perm.)
3 pairs of post-oral gnathobasic, masticatory head limbs; trunk limbs biramous, endopods gnathobasic.
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 26
fSUBCLASS BURGESSIDEA Walcott, 1912 (L. - M. Camb)
Trunk lacking lateral pleurae, limbs biramous; tail region with spikelike telson.
tOrder Burgessiida Walcott, 1912 {Burgessia Walcott, 1912)
tOrder Molariida Walcott, 1912 {Molaria Walcott, 1912; Emeraldoides Simonetta, 1964)
fOrder Habeliida Simonetta & delle Cave 1972 {Habelia Walcott, 1912; Thelxiopa; Economocaris)
TRILOBITOIDEA INCERTAE SEDIS Tontoia Walcott, 1912. Nathorstia Walcott, \9\2\Retifacies Hou,
Chen & Lu, 1989; Koumaia Hou, 1987; Rhombicalvaria. Hou, 1987; Helmetia Walcott, \9\lMollisonia
Walcott, \9\2\Urokodia Hou, Chen & Lu, 1989; Corcorania Jell, 1980; Serracaris Briggs, 1978?
tSUBCLASS TRILOBITA Walch, 1771 (L. Camb - U. Perm)
Trunk segments typically with lateral pleurae (trilobate); tail region pygidial.
tSuperorder Eotrilobitacea Whittington, 1977 (L. - M. Camb)
tOrder Nectaspida Raymond, 1920 {Naraoia Walcott, 1912) (Inch Liwia & Tegopelte, L. Camb)
tSuperorder Trilobitacea Walch 1771 (L. Camb - M. Perm)
tOrder Agnostida Kobayashi 1935
tOrder Redlichiida Richter, 1933
tOrder Corynexochida Kobayashi, 1935
tOrder Ptychopariida Swinnerton 1915
tOrder Phacopida Salter, 1964
tOrder Lichida Moore, 1959
tOrder Odontopleurida Whittington, 1959
tCLASS EMERALDELLIDEA Raymond, 1935 (M. Camb. - L. Dev.)
5 pairs of post-oral, gnathobasic, masticatory head limbs; trunk limbs biramous, endopods ambulatory.
tSUBCLASS SANCTICARIDEA E. L. Smith "Atlas" (M. Camb)
Pre-oral limb biramous; post-oral head limbs raptorial, unlike ambulatory trunk limbs; telson flabellate.
tOrder Sanctacarida E. L. Smith "Atlas" {Sanctacaris Briggs & Collins, 1988 [=Utahcaris orion Con-
way Morris & Robison, 1988]).
tSUBCLASS EMERALDELLACEA Raymond, 1935 (M. Camb - L. Dev)
Pre-oral limb uniramous, filiform; post-oral head and trunk limbs ambulatory and raptorial; telson a spike
tOrder Emeraldellida Simonetta & Della Cave, 1975, revised {Emeraldella Walcott, 1912)
tOrder Cheloniellonida Brioli, 1933 {Cheloniellon Broili, 1932) (L. Dev)
tOrder Aglaspida (Walcott, 1911) {Aglaspis Hall, 1862, revised Briggs et al, 1978) (L. Ord)
Inclusions: Aglaspella, Beckwithia, Palaeomerus; Borchgrevinkium; Palaeoniscus, Kodymirus?
Strabops?
SUPERCLASS CHELICERATA Heymons 1901 (L. Ord - R)
Pre-oral limb chelicerate, 3- (occasionally 2- or 4-) segmented; 5 (6) pairs of uniramous post-oral
head limbs; trunk limbs uniramous, respiratory.
CLASS MEROSTOMATA Dana, 1852 (L. Ord - R)
Post-oral head limbs gnathobasic, first pair undifferentiated; trunk limbs reduced to book gills; aquatic.
SUBCLASS XIPHOSURA Latreille 1802 (L. Ord -R)
Pre- and post-abdomen strongly differentiated; one pair of compound eyes.
Superorder Chasmataspididea Caster & Brooks, 1956, revised status (L. Ord - Dev)
Post-abdomen 9-segmented; pre-abdomen 3-segmented?
Order Chasmataspidida Caster & Brooks, 1950 (L. Ord-Sil) (Chasmataspis, Pseudoniscus)
Order Diploaspidida Caster & Brooks, 1956 revised status (Dev) {Diploaspis, Heteroaspis)
Superorder Xiphosuridea Latreille, 1802 (U. Sil. - R)
Post-abdomen 1 -3-segmented; pre-abdomen 7(8)-segmented.
tOrder Triopida Packard, 1886 (L. Ord) {Triopus )
tOrder Synxiphosurina Packard, 1886 (inch Weinbergina) (6 pairs post-oral head limbs)
Order Limulina Richter & Richter, 1929 (Carb - R) {Limulus L. 1787; + Euproops (Carb))
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 27
fSUBCLASS EURYPTERIDA Burmeister, 1843 (L. Ord - Perm)
Pre and post-abdomen not strongly demarcated; 2 pairs compound eyes
tOrder Eurypterida Burmeister, 1843 (Eurypterus)
tOrder Pterygota Clarke & Rudemann, 1912
CLASS ARACHNIDA Lamarck 1801 (Ord. - R)
Post-oral head limbs (secondarily) non-gnathobasic, first often differentiated as pedipalps; feeding
chelicerate; anterior trunk limbs forming book lungs or lacking; terrestrial
SUBCLASS SCORPINIATA Latreille, 1817 (Sil - R)
Order Scorpionida Latreille 1806 (Sil - R)
SUBCLASS PEDIPALPATA Latreille 1906 (M. Dev - R)
Order Palpigradida Thorell, 1881 (Jur - R)
Order Schizomida Petrunkevitch, 1945 (U. Tert - R)
Order Uropygida Thorell, 1882 (U. Carb - R)
Order Amblypygida Thorell 1883 (U. Carb - R)
Order Aranaea Clerck, 1757 (U. Carb - R)
tOrder Trigonotarbita Petrunkevitch, 1949 (M. Dev - U. Carb)
SUBCLASS PHALANGIATA Leach, 1915 (U. Carb - R)
Order Solfugida Leach 1815 (U. Carb - R)
Order Acarida Nitzsch 1818 (M. Dev - R)
Order Ricinulida Thorell, 1 892 (U. Carb - R)
Order Opilionida Sundevall 1833 (U. Carb - R)
Order Pseudoscorpiooida Latreille, 1817 (Olig. - R)
CLASS PYCNOGONIDA Latreille, 1910 (L. Dev - R)
Post-oral head limbs non-gnathobasic, first differentiated as pedipalps; feeding pharyngeal, pre-oral
limb assisted; aquatic.
tSUBCLASS PALAEOPYCNOGONIDA E. L. Smith Atlas (L. Dev)
tOrder Palaeoisopida Hedgepeth, 1978 (Palaeoisopus Broili, 1928)
tOrder Palaeopantopoda Broili, 1930 (Palaeopantopus Broili, 1928)
SUBCLASS PODOSOMATA Leach, 1813 (L. Dev - R)
Order Pantopoda Gerstaeker, 1963 {Pycnogonum littorale L.)
TABLE IV. SUGGESTED NATURAL CLASSIFICATION OF BUNTENNATE ARTHROPODS
2. INFRAPHYLUM BIANTENNATA Bergstrom, 1979 revised (= MANDIBULATA Clairville, 1798)
Head with acron and 2 pairs of positionally pre-oral limbs, 2nd pair embryonically post-oral, biramous- 3rd
(when present) mandibulate; trunk limbs not gnathobasic.
tSOTERCLASS EUTHYCARCINOMORPHA Handlirsch, 1914, revised status (L. Camb. - Trias)
Head 2(3)-segmented; head shield not maxillary; trunk tagmatized; thoracic limbs primitively biramous
endopods slender, multi-segmented, lacking terminal claws; abdomen limbless, with telson..
tCLASS EUTHYCARCINOIDEA Handlirsch, 1914 (L. Camb - U. Trias)
With the characters of the superclass.
tSUBCLASS FUXIANHUIATA new (L. Camb)
multi-segmented, segments simple, each with one pair of biramous limbs; telson short.
tOrder Fuxianhuiida new (Fuxianhuia protensa Hou, 1987)
INCERTA SEDIS: Chengjiangocaris longiformis Hou & Bergstiom, 1991.
tSUBCLASS EUTHYCARCINATA Handlirsch, 1914. (U. Carb - Trias)
Trunk with few (<20) diplo- and/or triplo- segments; trunk limbs uniramous, two per diplo-
segment; telson elongate.
tOrder Sottixeriformes Schram & Rolfe, 1982 (Pieckoxerxes piekoae Starobogatov, 1988)
tOrder Euthycarciniformes Schram & Rolfe, 1982 (Kottixerxes gloriosus Starobogotov, 1988)
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 28
fSUPERCLASS MARRELLOMORPHA Walcott, 1912, new status (M. Camb - L. Dev)
Head 2-4- segmented; head shield spinose or bivalved, not maxillary; mandible, endopod leglike; trunk not
tagmatized; trunk limbs undifferentiated, endopods strongly leglike, ambulatory, exceeds narrowly lamellate.
tCLASS MARRELLIDEA Walcott, 1912 (M. Camb - L. Dev)
Head 2-3 segmented; head shield with paired spines; telson minute.
tSUBCLASS MARRELLATA Walcott, 1912 (M. Camb)
Head 2-segmented; first post-oral head limbs antenna-like,
t Order Marrellida Walcott, 1912 (Marre/la Walcott, 1912)
tSUBCLASS MIMETASTERATA E. L. Smith "Atlas” (L. Dev)
Head 3-segmented; first post-oral head limbs leg-like,
tOrder Mimetasterida {Mimetaster Gurich, 1931)
fCLASS ACERCOSTRACA Lehmann, 1955 (L. Dev)
Head 4-segmented; head shield with carapace.
tSUBCLASS VACHONISIATA E. L. Smith "Atlas" (L. Dev)
Post-oral limbs 3 & 4 leglike, weakly gnathobasic.
tOrder Vachonisiida new (Vachonisia Lehmann, 1955)
tSUPERCLASS PHYLLOPODA Latreille, 1825 revised, restricted (M. Camb - L Ord)
Head 3-segmented; head shield bivalved, not maxillary; mandible masticatory, not leglike or palpate; trunk
15+ segmented, weakly tagmatized; endopods weakly leglike, exopods broadly lamellate (phyllopodous).
tCLASS BRANCHIOCARroEA E. L. Smith "Atlas" (M. Camb)
Head 3-segmented; trunk segments numerous (20+), with similar phyllopodous limbs.
tSUBCLASS BRANCHIOCARATA E. L. Smith "Atlas" (M. Camb)
First two pairs of head appendage prominent, 2nd pair cheliform?; carapace normal; tail region bifid.
tOrder Branchiocarida E. L. Smith "Atlas" (Branchiocaris Briggs, 1976)
tSUBCLASS ODARAIATA Simonetta & Delle Cave, 1975 (M. Camb)
Pre-oral appendages minute, linear?; carapace tubular; tail region trifid.
tOrder Odaraiida Simonetta & Delle Cave, 1975 {Odaraia Walcott, 1912)
tCLASS (SUBCLASS) CANADASPIDIDEA Novoshilov, 1960 (M. Camb - L, Ord)
Head appearing indistinctly 5-segmented, posterior 2 pairs of limbs similar to trunk limbs; trunk
15-segmented, posterior 7 segments lacking paired appendages.
tOrder Canadaspidida (Canadaspis Novoshilov, 1960; Perspicaris Briggs, l911\?Rhebachiella
kinnekullensis Muller 1983 (larval stages)
?Order Hymenostraca Rolfe, 1969 {Hymenocaris Salter, 1853) (M. Camb - L. Ord)
SUPERCLASS CRUSTACEA Pennant, 1777 (after Schram, 1986) (M. Camb - R)
Head with pre-oral antenna and 4 post-oral limbs, first antennalike, 2-4 (including mandible) masticatory;
head shield maxillary; trunk often tagmatized, limbs often differentiated, specialized; telson present.
CLASS (SUBCLASS) REMIPEDU Yager, 1981 (M. Dev - R)
tOrder Enantiopoda Birshtein, 1960 (Tesnusocaris Brooks, 1955) (M. Dev)
Order Nectiopoda Schram, 1986 {SpeleonectesYdigQX, 1981) (R)
CLASS BRANCHIOPODA Latreille, 1817 (L. Dev - R)
SUBCLASS SARSOSTRACA Tasch, 1969 (M. Dev - R)
tOrder Lipostraca Scourfield, 1926 (M. Dev)
Order Anostraca Sars, 1867 (L. Dev - R)
SUBCLASS CALMANOSTRACA Tasch, 1969 (M. Dev. - R)
Order Notostraca Sars, 1867 (L. Dev - R)
AMPHIPACIFICA VOL. II. NO. 1 AUG. 31, 1995 29
Order Kazacharthraca Novozhilov, 1957 (L. Jur)
Order Conchostraca Sars, 1867 (L. Dev - R)
Order Cladocera Latreille, 1829 (Perm-R)
CLASS (SUBCLASS) CEPHALOCARIDA Sanders. 1955 (R)
Order Brachypoda Birshtein, 1960 (Hutchinsoniella Sanders, 1955)
CLASS MAXILLOPODA Dahl, 1956 (L. Camb - R)
tSUBCLASS SKARACARIDA Muller, 1983 (M. Camb - U. Camb))
Order Skaracarida Muller, 1983. Skara annulata Muller, 1983) (several other, mostly larval genera
e.g., Dala, Walossekia, Oelandocaris, Bredocaris,
SUBCLASS OSTRACODA Latreille, 1836 (L. Camb - R)
fOrder Bradoriidae Matthew, 1902
t Order Phosphatocopida K. J. Muller, 1964 (L. Camb. - L. Ord)
tOrder Leperditicopida Scott, 1961 (U. Camb - U. Dev)
fOrder Palaeocopida Henningsmoen, 1953 (L. Ord - Trias)
Order Halocyprida Dana 1852 (Sil - R)
Order Platycopida Sars 1866 (L. Ord - R)
Order Cladocopida Sars 1866 (Ord - R)
Order Myodicopida Sars, 1966 (Ord - R)
Order Podocopida Sars, 1866 (Sil - R)
SUBCLASS THECOSTRACA Gruvel, 1905 (M. Camb - R)
Order Facetotecta Gruvel, 1905
Order Rhizocephala F. Muller, 1862
Order Ascothoracida LacazcrDuthiers, 1880
Order Cirripedia Burmeister, 1834 (M. Camb - R)
SUBCLASS TANTULOCARIDA Boxshall & Lincoln, 1983 (R)
Order Tantulocaridida Boxshall & Lincoln, 1983
SUBCLASS COPEPODA Milne-Edwards, 1840 (Cret - R)
Order Calanoida Sars, 1903
Order Harpacticoida Sars, 1903
Order Cyclopoida Burmeister, 1834
Order Misophrioida Gurney, 1933
Order Monstrilloida Sars, 1903
Order Siphonostomatoida Thorell, 1859 emend Sars 1918
Order Poecilostomatoida Thorell 1 859
SUBCLASS LINGULATULIDA Frolich, 1789 (=Pentastomatida Rudolphi 1819) (R)
Order Cephalobaeniuda Heymons & Vitzthum, 1936
Order Porocephalida Heymons & Vitzthem, 1936
tCLASS (SUBCLASS) THYLACOCEPHALA Pinna, Arduini et al. 1982. (Camb? L. Sil - Cen)
tOrder Concavicarida Briggs & Rolfe, 1983 (L. Sil - Cen)
tOrder Conchyliocarida Secretan, 1983 (Camb? - Jur)
CLASS MALACOSTRACA Latreille 1806 (Dev - R)
SUBCLASS PHYLLOCARIDA Packard, 1879 emended (Dev - R)
tOrder Archaeostraca Claus, 1888
tOrder Hoplostraca Schram, 1973
Order Leptostraca Claus, 1880 (see also Dahl, 1984)
SUBCLASS HOPLOCARIDA Caiman 1904 (U. Dev - R)
tOrder Aeschronectida Schram, 1969 (Carb)
tOrder Palaeostomatopoda Brooks, 1955 (U. Dev - L. Carb)
Order Stomatopoda Latreille, 1817 (Carb-R)
SUBCLASS EUMALACOSTRACA Grobben, 1892 (modified from Schram, 1986) (U. Dev - R)
Superorder Syncarida Packard, 1885 (U. Carb - R)
tOrder Palaeocaridacea Brooks, 1962
AMPHIPACinCA VOL. H. NO. 1 AUG. 31, 1995 30
Order Anaspidacea Caiman, 1904
Order Bathynellacea Chappuis, 1915
Order Stygocaridacea Noodt ,1964
fSuperorder Belotelsonidea Schram, 1981
tSuperorder Waterstonellidea Schram, 1981
fSuperorder Eocaridacea Brooks, 1962
Superorder Thermosbaenacea Monod, 1927
Superorder Mysidacea Boas, 1883
Order Lophogastrida Boas, 1883
fOrder Pygocephalomorpha Beurlen, 1930
Order Mysida Boas 1883
Superorder Amphipoda Latreille, 1916
Superorder Hemicaridea Schram, 1981 emended
Order Spelaeogriphacea Gordon, 1957
Order Mictacea Bowman et al. 1985
Order Cumacea Kroyer, 1846
Order Tanaidacea Dana, 1853
Superorder Isopoda Latreille, 1817
Superorder Eucarida Caiman, 1904
Order Euphausiacea Dana, 1862
Order Amphionidacea Williamson, 1973
Order Decapoda Latreille, 1803
SUPERCLASS MYRIAPODA Latreille, 1796 (Sil - R) (Essentially terrestrial; not detailed here)
Head with embryonic acron, pre-oral antenna, 5 post-oral pairs of masticatory limbs (1st post-oral embry-
onic); trunk not tagmatized, with more than 20 pairs of ambulatory limbs, ending in telson.
CLASS SYMPHYLA Ruder, 1880 (1 subclass) (Olig-R)
CLASS CHILOPODA Latreille, 1802 (2 subclasses) (M. Dev - R)
CLASS PAUROPODA Lubbock, 1866 (1 subclass) (R)
CLASS DIPLOPODA Gervais, 1844 (3 subclasses) (Sil - R)
fCLASS ARTHROPLEURIDEA Zittel, 1848 (1 subclass)(L. Dev - U. Carb)
SUPERCLASS HEXAPODA (L. Dev. - R.) (Essentially terrestrial; not detailed here)
Head with acron + pre-oral antenna, 4 post-oral pairs masticatory limbs (1st post-oral embryonic, 2nd mand-
ibulate; trunk tagmatized; thorax with 3, abdomen with 11 (max.) pairs ambulatory limbs; telson embryonic.
CLASS PARINSECTA (2 Subclasses: CoUembola, Protura) (L. Dev - R)
CLASS INSECTA (2 Subclasses Entognatha, Ectognatha) (U. Carb - R).
TABLE V. NUMBERS OF fflGHER ARTHROPOD TAXA SINCE CAMBRIAN TIMES.
P
E R I
O
D
ARTHROPOD
INFRAPHYLA
I
CAMBRIAN
(545-495 mybp)
II
LATE PALEO-
ZOIC
(-300 mybp)
ni
TERTIARY-
RECENT
(0-30 mybp)
IV
TOTALS
SPCL. CL.
SBCL.
SPCL. CL.
SBCL.
SPCL. CL. SBCL
SPCL.
CL. SBCL.
UNIANTENNATA
2 8
11
3 5
8
1 3 5
3
10 18
BIANTENNATA
4 6
9
5 11
24
3 12 24
6
18 34
TOTAL
ARTHROPODA
6 14
20
8 16
32
4 15 29
9
28 52
AMPHIPACIFICA VOL. H. NO. 1 AUG. 31, 1995 31
Arthropod Diversity and Evolutionary Trends
Table V summarizes (from Tables m & IV) the number
of higher arthropod taxonomic categories, recognized here at
superclass (SPCL), class (CL) and subclass (SBCL) levels,
that are represented by known genera and species of the
Cambrian, late Paleozoic and Tertiary-Recent Periods.
Analysis of the changing numbers with geological time re-
veals interesting and perhaps significant evolutionary trends .
Despite the very great difference in numbers of species
known for each of the three time-scale samplings (Cambrian
~102 species; Late Paleozoic- ~10 "^-i-species; Tertiary-Re-
cent — 10 ^ + species), the numbers of higher taxa are of
comparable orders of magnitude for all categories. In the
600-million-year time span since the presumed dawn of
arthropod life (Ediacrian, Vendian), we here categorize only
9 superclasses, 28 classes and 52 subclasses to encompass
the entire known fauna, past and present, of well over one
million described species (Table V, Col. IV, bottom row).
Fully one- third of the early subclasses is known from only 1-
10 species, a fact suggesting the likelihood of further new
discoveries, at that level or higher, among incompletely
described or totally new fossil material. Only one of the 9
superclasses (Crustacea), one of the 28 classes (Maxillopoda)
and only two of the 52 subclasses (Ostracoda, Thecostraca)
have actually been recorded throughout this immense
paleontological range. To this meager total we might add the
Chelicerata but it is presently confirmed not earlier than
Lower Ordovician. However, further analysis of Paleozoic
fossil material is expected to extend the time range of extinct
species forwards, and recent species (especially minute,
soft-bodied forms), backwards in time. Thus, the morph-
ologically primitive Remipedia and Cephalocarida may
have originated during Cambrian times, despite their very
limited or non-existent fossil records (see Hessler, 1984).
Aquatic larval stages of some other classes of Crustacea and
of the merostomatid uniantennates (e.g., phyllocarid and
trilobite larvae, respectively), tend to recapitulate adult mor-
phology of extinct, but related, Cambrian categories.
Thus, by the Cambrian Period, 67 % (6/9) of the super-
classes, but only -50% (14/28) of the classes and -38% (20/
52) of the subclasses had evolved. By the late Paleozoic,
perhaps the heyday of arthropod evolution generally, nearly
all (8/9) the superclasses, and -60% (16/28; and 32/52) of
all classes and subclasses were represented. Today, however,
scarcely half (4/9 and 15/28) the superclasses and classes
persist, and the percentage of subclasses, 56% (29/52), has
also dropped slightly.
If trends are analysed according to infraphylum for
each time interval, for the uniantennates the percentages
were highest during the Cambrian, with 33% (2/6) of the
superclasses, 57% (8/14) of the classes, and 55% (1 1/20) of
the subclasses. However, the group decreased markedly in
importance by the late Paleozoic (only 37% of superclasses,
-3 1% of classes, and -25% of subclasses), and is lowest to-
day (25% of superclasses, -20% of classes, and only -17%
of subclasses). By contrast, the biantennates increased
steadily from lowest values in the Cambrian (67% of super-
classes, 43% of classes and 45% of subclasses), through the
late Paleozoic (63% of superclasses, -70% of classes, and
-67% of subclasses), to maximum dominance today (75% of
superclasses, -80% of classes, and -83% of subclasses).
These changes in relative numbers of the two arthropod
infraphyla may reflect the impact of the evolution of vascular
plants during Silurian-Devonian and later periods (Kukalova-
Peck, 1987). That event provided an enormous new food
resource in both aquatic and terrestrial environments. These
nutrients could be exploited by the omnivorous aquatic
crustaceans and terrestrial myriapods and hexapods by direct
adaptation and diversification of feeding morphology and
style (as in malacostracan crustaceans, and winged insects).
By contrast, the uniantennates were more or less “locked
into” their mainly carnivorous, and some detritivorous life
styles; they could take only indirect advantage of this food
resource, and only by developing new predatory morph-
ologies and life styles, especially within the terrestrial
environment. They are now a secondary part of the terrestrial,
and a minute relict part of the aquatic, arthropod fauna.
With respect to the level of arthropod disparity during
Cambrian times, the positions of both Gould (1989) and
proponents to the contrary (e.g., Ridley, 1993; Wills et al.
1994) receive support from the present analysis. Thus, of 9
"all-time" arthropod superclasses, 7 (including Chelicerata)
were represented in Cambrian and Lower Ordovician fau-
nas, but only 4 are represented in the Recent fauna. Espe-
cially remarkable is the fact that Cambrian arthropods were
entirely aquatic, and were represented by less than 100
species from a very limited series of marine habitats. The
two superclasses missing from the Cambrian record, the
Myriapoda and the Hexapoda, are both essentially terres-
trial. Thus, if only aquatic faunas are considered, the
disparity level of Cambrian arthropods is more than 3 times
greater (7 vs. 2 superclasses) than today.
On the other hand, at class level, disparity levels are
similar ( 14 vs. 15), and at subclass level, the Recent arthropod
fauna is about 50% richer (29 vs. 20). Furthermore, all of
the arthropod, or arthropodlike, species of the Burgess Shale,
designated by Gould (1989) and Briggs et al. (1993) as new
(or probably new) at phylum and/or infraphylum levels, can
be adequately encompassed within existing class and/or
superclass categories.
Thus, it is concluded here that, during the entire evolu-
tionary history of the Arthropoda, disparity levels were at or
near maximum during the Cambrian Period. Such a high
level, close to the starting point of the arthropod fossil rec-
ord, is consistent with the probable correctness of the evol-
utionary theory of punctuated equilibrium (Eldridge & Gould,
1972). Since invertebrate faunas of early "explosive evolu-
tionary" times were not described comprehensively until the
early 20th century (e.g., Walcott (1912), and later), Charles
Darwin (1859) may be excused for missing that part of the
evolutionary story.
AMPHIPACMCA VOL. II. NO. 1 AUG. 31, 1995 32
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OpaBiniaTyttBs WaCcott
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(SdananneCofBns UCustration,
modified from Qotdd, 1S8S)
AMPHIPACinCA VOL. 11 NO. 1, AUG. 31, 1995 35
THE AMPHffOD SUPERFAMILY PONTOPOREIOIDEA ON THE PACIFIC COAST OF NORTH AMERICA.
I. FAMILY HAUSTORHDAE. GENUS EOHAUSTORIUS J. L. BARNARD: SYSTEMATICS AND
DISTRIBUTIONAL ECOLOGY
ABSTRACT
by E. L. Bousfield^ and Phillip Hoover^
On the Pacific coast of North America, from the Bering Sea to Southern California, the free-burrowing
gammaridean amphipod family Haustoriidae is represented by six species of Eohaustorius Barnard, 1957.
On the Asiatic Pacific coast six species, all subtidal, have now been described. A single northern subtidal
species, E. eous, connects the two faunas in the Bering Sea region.
This paper describes E. bamardi, new species, from off Pt. Conception, California, and provides re-
descriptions, keys and new distributional information for Eohaustorius eous (Guijanova, 1951), E. estuarius
Bosworth, 1973, £. sawyeri Bosworth, 1973, E. brevicuspis Bosworth, 1973, E. sencillus Barnard, 1962 and
E. washingtonianus (Thorsteinson, 1941). Material ascribed to the latter species from the northwestern
Pacific region by Gurjanova (1962) is herewith redescribed as E. gurjanovae, new species. Subtidal material
from South Korea is described as E. longicarpus, new species.
The species of Eohaustorius are morphologically variable throughout their ranges, especially E.
washingtonianus, but variation is not considered of species or subspecies value. Cluster analysis reveals three
main subgroupings, none very closely inter- or intra-related, viz: a North American endemic group of E.
washingtonianus Barnard, E. brevicuspis Bosworth and E. bamardi, new species; an Asiatic Pacific group
of E. cheliferus Bulcheva, E. subulicolus Hirayama and E. robustus Gurjanova; and a northern relatively
primitive core group of E. eous (Guijanova), E. sawyeri Bosworth, E. gurjanovae, new species, E. estuarius
Bosworth, E. longicarpus, new species, and E. sencillus Barnard. The Asiatic species have relatively
restricted distributions and none is intertidal. This hiatus results presumably from competition with intertidal
members of amphipod family Dogiehnotidae dominant in that region, and from severe physical factors in
winter of low intertidal temperatures and ice scour. On the North American Pacific coast, however, all species
have relatively wide geographical ranges, and four species are intertidal. There, only one species of
Dogiehnotidae, Proboscinotus loquax, provides intertidal competition, and the climate is equable year-round
winter ice scour is .lacking.
The genus Eohaustorius is sufficiently similar to North American Atlantic haustorinid genera as to
preclude separate evolution from a pontoporeiid ancestor and thereby render polyphyletic the family
Haustoriidae. However, the genus Eohaustorius is cold-temperate, and the Atlantic-endemic genera are
warm-temperate, in biogeographical affinities. Eohaustorius is closest morphologically to the Atlantic sub-
tidal genus Pseudohaustorius, thereby raising the possibility that during early Miocene times, prior to emerg-
ence of the isthmus of Panama, a common ancestor connected the two groups via a southern marine waterway.
INTRODUCTION
The superfaimly Pontoporeioidea is a relatively small
group of fossorial amphipods, whose marine members are
foundmainly in sedimentary substrata along holarctic shores.
Members of the primitive family Pontoporeiidae tend to be
arctic and sub-arctic in distribution, with a significant com-
ponent confined to glacial relict freshwater lakes of North
America and northwestern Eurasia (Bousfield, 1987). By
contrast, members of the advanced and highly specialized
family Haustoriidae are marine and estuarine and occur
mainly along warm-temperate and boreal coastlines of the
North Atlantic and North Pacific regions (Bousfield, 1965;
1970, 1973). On the Pacific coast of North America, family
Pontoporeiidae is sparsely represented (Bousfield, in prep:
Priscillina and Monoporeia in the Bering Sea, Pontoporeia
in glacial Qords, and Diporeia in a few post-glacial lake
basins). However, owing mainly to the work of Thorsteinson
T
(1941), Gurjanova (1951, 1962), Barnard (1957, 1962),
Bosworth (1973) and Coyle & Mueller (1981), the family
Haustoriidae is known to be moderately speciose in shallow,
high energy coastal marine waters from the Bering Sea coast
of Alaska to southern California. The genus is well represented
in coastal waters of Korea and Japan (Ishimarus, 1994), and
along the Russian coast north to the Bering Sea region, but
not in Arctic waters.
Within the North Pacific region generally, the family
Haustoriidae is represented only by the single genus,
Eohaustorius Barnard, 1957. Some seven species of this
genus have been recorded from the North American Pacific
coast and another five from the Pacific coast of Russia and
the Japan Sea (including Korea). The genus is distinct from
the North Atlantic complex (with the European species
Haustorius arenarius (Slabber) as type) in having peraeopods
3 and 4 unlike in size and form, and telson lobes widely sep-
arated on the dorsum of urosome 6, among other differences .
Research Associate, Royal Ontario Museum, Toronto, Ontario. M5S 2C6.
Research and Teaching Assistant, Department of Biology, University of Victoria, Victoria, B. C. V8W 2Y2.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 36
This study treats the systematics and distributional ecol-
ogy of species of the genus Eohaustorius in North Pacific
coastal marine region, and emphasizes the North American
Pacifica fauna.
Species of Eohaustorius have proven useful as indicators
of sediment quality (see Bousfield, 1991; Mcleay et al.
(1990); Yeeetal. 1992).
Acknowledgements. The present North American
haustoriid material was accumulated mainly as a result of
National Museum, now Canadian Museum of Nature (CMN),
field expeditions, conducted by one of us (ELB) and
colleagues, during the period 1955-1980. Complete lists of
stations, pertinent data and acknowledgement of field
assistance are provided elsewhere (Bousfield, 1958, 1963,
1 968 ; Bousfield & McAllister, 1 962; and Bousfield & Jarrett,
1981). Additional material was provided by Drs Peter
Slattery, Moss Landing, California; Charles O' Clair, Auke
Bay, Alaska; Kathleen Conlan CMN, Ottawa, and McLeay
Associates, West Vancouver. The authors are most grateful
for use of the laboratory facilites of Dr D. V. Ellis, University
of Victoria, and for the use of collections and facilities of the
CMN in Ottawa.
The authors are indebted to Dr Weldon S. Bosworth for
his pioneering work on much of this material in 1973-4, and
for his unpublished commentary and distributional informa-
tion. Susan Laurie-Bourque very capably assisted in
preparation of the line drawings. Marjorie A. Bousfield
provided translations of pertinent Russian literature. The
illustrative work was supported under a research divisional
grant of the Royal Ontario Museum, Toronto.
SYSTEMATICS
Haustoriidae Stebbing
Haustoriidae Stebbing, 1906: 118. — Guijanova, 1951:328;
1962: 395.— Bousfield, 1965: 165 (part); 1973: 99 (part);
1982: 259. — Barnard and Drummond, 1982: 136. —
Hirayama, 1985: 395. — Barnard & Karaman, 1991: 357.
Taxonomic commentary. B amard and Karaman (1991)
have provided a simplified key to genera of Haustoriidae
(sensu strictu).
With respect to superfamily classification, Barnard &
Karaman (loc. cit.) have continued recognition of family
Haustoriidae as the type of superfamily Haustorioidea,
proposed initially by Barnard & Drummond (1982). As
shown by Bousfield (1982b, 1990) and Bousfield & Shih
(1994), the Bamardian concept (of Haustorioidea) includes
most members of family Urothoidae and other superficially
and convergently similar families. The latter groups are
phyletically more correctly placed within superfamily
Phoxocephaloidea (e.g., Bousfield 1982, 1990; and Schram,
1 986). In all major character states, family Haustoriidae is
most clearly related to members of family Pontoporeiidae,
and thus phyletically assignable to the superfamily which the
latter typifies, the Pontoporeioidea. As shown above
(Bousfield, loc . cit.), these major pontoporeioidean character
states of Haustoriidae, especially of its most primitive genus
Protohaustorius, include its short broad, weakly rostrate
head, "pseudorostrate" paired peduncles of antenna 1 , weakly
(or non-) dactylate peraeopods and maxilliped, lack of coxal
gill on peraeopod 7, unique form of the pleopods (lacking
clothespin spines), strongly deflexed urosome, and the
holarctic (non-antipodean) distribution of nearly all member
species. The character states of the Pontoporeioidea,
especially the phyletically significant antennal calceoli, are
basically gammaroidean and not phoxocephaloidean or
crangonyctoidean in form.
Eohaustorius J. L. Barnard
Eohaustorius J. L. Barnard, 1957: 81. — Gurjanova, 1962:
400.— Bousfield, 1970: 150.— Bosworth, 1973: 160.— Barn-
ard, 1975: 348 (key). — Hirayama, 1985: 43. — Barnard &
Karaman, 1991: 361. — Ishimaru, 1994: 64.
Type species. Haustorius washingtonianus Thorsteinson,
1941, original designation.
Component species. E. tandeensis Dang, 1968; E.
subulicolus Hirayama, 1985; E. cheliferus (Bulycheva,
1952); E. eous (Guijanova, 1951); £. robustus (Gurjanova,
1953; E. sawyeri Bosworth, 1973; E. brevicuspis Bosworth,
1973; E. estuarius Bosworth, 1973; E. longicarpus, new
species; E. gurjanovae, new species; E. sencillus Barnard,
1962; E. bamardi, new species.
Diagnosis. Body short, broad. Head broad; rostrum
short, acute. Pigmented eyes essentially lacking. Antennal,
flagellum 5-segmented; accessory flagellum 2-segmented,
attached subapically to peduncular segment 3, bearing
aesthetascs. Antenna 2, peduncle 4 broadly lobate and
strongly setose behind; peduncle 5 broad, not lobate behind;
flagellum 4-5 segmented.
Upper lip rounded. Lower lip, inner lobes with short
proximal processes. Mandible, molar strong triturative;
incisor acute; palp segment 3 with few (5-15) inner marginal
comb spines. Maxilla 1 lacking accessory basal baler lobe;
inner plate with single apical seta; outer plate with 8-9 apical
spines. Maxilla 2, outer plate little larger than inner, not
lunate inform; innerplate with weak facial setae. Maxilliped,
inner plate with 2 apical spines; outer plate very large,
exceeding palp segment 2; palp segment 3 clavate, not genic-
ulate.
Coxal plates 1 & 2 small, 3 & 4 squarish below.
Gnathopod 1, segment 3 very short; segment 5 relatively
short, deep; segment 6 medially deepest. Gnathopod 2,
segment 3 very short; segment 5 with postero-distal cluster
of specialized spines; segment 6 short, medially swollen,
arcuate, produced beneath minute dactyl to form a microchela .
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 37
KEY TO NORTH PACIFIC SPECIES OF EOHAUSTORIUS
1. Pleon plate 3 strongly produced behind into a recurved hooklike process; peraeopod 4, hind lobe of
segment 5 elongate, slender, length 4-5 X width (depth); uropod 3, inner ramus with single small inner
marginal seta; Asiatic coast £. subulicolus (p. 42)
— Pleon plate 3, hind process nearly straight, if hooked, not recurved; peraeopod 4, segment 5, hind lobe
shorter, deeper, length less than 2 X depth; uropod 3, inner margin with 2-6 setae 2.
2. Peraeopod 6, segment 4 tall, length 2X width, with 5-6 groups of facial spines (in addition to marginal
spines); basis slender, distinctly narrower than length (depth), subovate; uropod 1, hind margin of inner
ramus with 2 single setae; gnathopod 1, dactyl, body large, length > nail (unguis) 3.
—Peraeopod 6, segment 4 subtriangular, widest distally, length < 2X width; basis as broader or broader
than length; gnathopod 1, dactyl, nail longer than body 4 .
3. Antennae 1 & 2, flagella 5-segmented; peraeopod 4, hind lobe elongate, ~2 X depth; abdominal side
plate 3, apex abruptly upturned, minutely split-tipped E. longicarpus (p. 56)
—Antenna 1 & 2, flagella 3-segmented; peraeopod 4, segment 5, hind lobe short, length not greater than
depth; abdominal side plate 3, hind process straight or apex slightly upturned E. sencillus (p. 44)
4. Peraeopod 4, segment 5, posterior lobe, distal margin with spine cluster; peraeopod 6, segment 4 with
lower facial row of 2-3 spine groups; peraeopod 6, segment 5 with posterior marginal spine^roup . . 7.
Peraeopod 4, segment 5, distal lobe base, smooth; peraeopod 6, segment 4 with at least one other spine
cluster above lower row; peraeopod 6, segment 5 lacking posterior marginal spines 5.
5. Peraeopod 7, basis, hind margin proximally with strong cusp or tooth; pleon plate 3 produced, poster-
iorly as weak tooth £ washingtonianus (p. 50)
Peraeopod 7, basis hind marginal tooth weak or rounded; pleon plate 3, process strong 6.
6. Peraeopod 7, basis wider than deep, hind cusp rounded; maxilliped palp, segment 3 strongly broadened
distally, width = 3/4 length e. brevicuspis (p. 50)
Peraeopod 7, basis not wider than deep, hind cusp acute; maxilliped palp, segment 3 normal, length ~2X
bamardi (p. 54)
7. Peraeopod 4, segment 5, hind lobe strongly produced, width of segment 2 X depth (length); peraeopod 7,
segment 6 with 2 posterior marginal groups of spines; gnathopod 2, basis, hind margin with distal setae only
cheliferus (p. 55)
— Peraeopod 4, segment 5, hind lobe normal, width about equal to length; peraeopod 7, segment 6 with 3-4
posterior marginal spines groups; gnathopod 2, basis, hind margin setose throughout 8.
8. Peraeopod 5, segment 4 widest distally, 2X length; pleon plate 3, postero-dorsal process large, strongly
overhanging urosome; uropod 3, inner ramus with 2-3 marginal setae E. sawyeri (p. 44)
Peraeopod 5, segment 4 less broad, ~ 1.5X length; pleon overhang normal, little or not exceeding side
plate process; uropod 3, inner ramus with 5 marginal setae 9
9. Peraeopod 7, segment 6 with 2 groups of posterior marginal spine groups; coxae 3 & 4 antero-distal mar-
gins rounded Eestuarius (p. 40)
Peraeopod 7, segment 6 with 3-4 posterior marginal spine groups; coxae 3 & 4 squarish 10.
10. Peraeopod 5, segment 6 with 1 group of anterior marginal spines; pleon plate 3 , hind process, apex
slightly upturned; peraeopod 4, segments 5 & 6 lacking anterior marginal spines; peraeopod 7, basis
veiy broad, exceeding length £ (p 43 ^
—Peraeopod 5, segment 6 with 2 groups anterior marginal spines; pleon plate 3 hind process straight; per-
aeopod 4, segment 5 & 6 with anterior marginal spines; peraeopod 7, basis not wider than deep . . .\ 1 1.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 38
11. Peraeopod 7, segment 6 with 4 posterior marginal spines; basis lacking posterior cusp; mandibular palp
segment 3 with 14-15 posterior marginal comb spines E. eous (p. 38)
— Peraeopod 7, segment 6 with 3 posterior marginal spines; basis with rounded posterior proximal cusp;
mandibular palp segment 3 with 8-9 posterior marginal comb spines E. gurjanovae (p. 47)
Peraeopod 3, segment 4 short, triangular; 5 weakly lob-
ate behind; 6 small, margins spinose, not setose. Peraeopod
4 smaller and unlike peraeopod 3 in form; segment 3 very
short, 4 little broadened, 5 strongly produced and spinose
behind; 6 slender, distally spinose and setose.
Peraeopod 5, basis broad, hind margin setose, with
proximal cusp; segments 4-6 not broader than long, outer
face with spine clusters . Peraeopod 6 longest; basis medium
broad, hind margin setose, with proximal cusp; segment 4
often longer than broad; segment 5 broader than long, with
prominent antero-distal process and distal marginal notch;
segment 6, some distal spines split-tipped. Peraeopod 7,
basis very broad hind margin nearly bare, proximal cusp low
or lacking; segment 4 broad, triangular; segment 5 broad.
Pleon segment 3 strongly deflexed posteriorly, postero-
distal lobe strong, overhanging urosome. Pleon plate 3, hind
comer acutely produced. Pleopods powerful; peduncle
short, broad; outer ramus 10-16 segmented, inner shorter,
with proximal baso-medial lobe.
Urosome short, lacking antero-distal lappet. Uropod 1,
rami cylindrical, inner ramus with posterior marginal setae
only. Urosome 2 short, not occluded dorsally. Uropod 2,
rami heavily setose, subequal. Uropod 3, rami short, <2X
peduncle, terminal segment variable. Telson lobes widely
separated at base; each with dorso-lateral marginal setae, and
single apical penicillate seta.
Coxal gills saclike, on peraeopods 2-6. Brood plates
relatively narrow, elongate.
Distribution. Member species are endemic to the North
Pacific coastal shelf regions of eastern Asia, and North
America, from the Bering Sea to Vietnam in the west, and in
the east, south to Baja California.
Taxonomic commentary. Eohaustorius is distinct
from North American Atlantic genera in the unlike form of
peraeopods 3 & 4 and the widely separated telson lobes.
However, in the short antennal flagella, form of the lower lip,
maxilla 1 & 2, maxilliped, processiferous pleon plate 3, and
setose telson, it more closely resembles the warm-temperate
North Atlantic genus Pseudohaustorius (Fig. 2, p. 41) than
the type genus Haustorius (Fig. 2.2). Such basic similarities
suggest a former ancestral link with the diverse Atlantic
haustoriid complex via the submerged Panama isthmus
(Bousfield, 1970) (see also pp. 61-62).
Eohaustorius eous (Gurjanova)
<Figs. 1, 2)
Haustorius eous Gurjanova, 1951: 331.
Eohaustorius eous eous Gurjanova, 1962: 406.
Eohaustorius eous Barnard & Karaman, 1991: 463. — Ishi-
maru, 1994: 64.
LEGEND FOR FIGURES
A1
antenna 1
MX 1 -
maxilla 1
A2
antenna 2
MX2 -
maxilla 2
BR.
coxal gill
MXPD -
maxilliped
BR SET -
brood plate seta
O.P. -
outer plate
COXAE -
coxal plates
PLP -
palp
DACT -
dactyl
P3-P7 -
peraeop'ds 3-7
EPl-3 -
pleon plates 1-3
RT
right
GNl
gnatho;od 1
SP
spine
GN2 -
gnathopod 2
T
telson
I.P.
inner plate
U1-U3 -
uropods 1-3
I.R.
inner ramus
UROS -
urosome
LFT
left
X
magnified
LL
lower lip
o
male
MD
mandible
0
female
Material examined.
ALASJCA. Bering Sea: Northeast end of St. Lawrence I., Lot
#1, 20 m sand, P. Slattery coll., July 10, 1980 - 2 males, 4
females, 1 im, CMN Cat. no. NMCC 1991-1209; Ihid.. Lot #5
- 2 males, 13 female, 5 im.
St. Mathew I., Walrus Cove, sand, 8 m,P. Slattery coll., 1983
- 1 im; Ibid .. 11m scoop, sand - 3 males, 1 1 females, 2 im;
Ibid .. 13 m, sand - 2 males, 21 females, 14 im. CMN Cat. no.
NMCC1991-1206.
St. Paul L, English Bay, 3 m scoop, P. Slattery coll., 1983,
- 5 males, 37 females, 8 im; Ibid .. 10 m sand - 3 males, 9
females, 2 im; Ibid ., reef, 20 m - 1 female ov (5.5 mm) slide
mount, 3 females (5.5 mm, 5.5 mm, 4.5 mm)+ 1 male, 4
females, 15 im, NCMNB Cat. no. NMCC1991-1204; Ibid ..
25 m sand - 3 males, 36 females, 15 im, CMN Cat. no.
NMCC1991-1203.
Alaska mainland: 30 miles west Cape Rodney, 24 m. dive, P.
Slattery coll., 1981 - 6 females, 3 im, CMN Cat. no. NMCC-
1991-1211.
Diagnosis. Female (6.0 mm): Head, rostrum short.
Pigmented eyes lacking. Antenna 1, segment 2 strongly
setose anteriorly; accessory flagellum inserted nearly apic-
ally. Antenna 2, peduncular segment 4, postero-distal lobe
medium; posterior margin lined with numerous (>40) plumose
setae; segment 5 medium broad, widest distally; flagellar
segment 1 with postero-distal setal cluster.
Mandible, palp segment 3 with 14-15 posterior mar-
ginal comb spines. Maxilla 2, inner plate with distinct facial
row of 6-7 plumose setae. Maxilliped, outer plate medium;
palp segment 2, inner lobe large, broad, reaching almost to
tip of narrowly clavate segment 3.
Coxae 1 & 2. Gnathopod 1 , segment 5 relatively short,
deep; segment 6 medium, arcuate. Gnathopod 2, hind margin
long-setose; segment 5 slender, shallow, distal spines slender.
Peraeopod 3, coxa squarish; segment 4 short, distally
broad; segment 5 strongly setose proximally; segment 6
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 39
FIG. 1. Eohaustorius eous. (Gurjanova). Female ov. (5.0 mm). Bering Sea, Alaska. Slattery coU.
ovate, margins spinose. Peraeopod 4, segment 4 with 23
posterior marginal setae; segment 4 hind lobe short, distally
broad, truncate, anterior margin with 1 stout spine group;
segment 6 slender, with 21 anterior marginal spine group.
Peraeopod 5, basis broadly ovate, hind margin com-
pletely lined with setae; segment 4 short, uniformly broad;
facial spine clusters strong; segment 5 medium, not wider
than long, facial spine clusters strong; segment 6 broadest
medially, anterior margin with 2 spine clusters, posterior
margin with 2 single spines. Peraeopod 6, basis medium,
hind margin setose throughout; segment 4 elongate, with 3-
4 facial spine clusters; segment 5 broadest distally, with 2
weak facial spine groups, 4-5 inner distal and 5-6 outer distal
marginal spines; antero-distal emargination medium deep;
segment 6 relatively long and slender, with 4-5 clusters of
mixed long and short spines. Peraeopod 7, basis broad, hind
margin distally narrowing and lined with medium setae;
segment 4 slightly wider than long, anterior margin with 3
spine clusters, posterior margin lined with long setae; seg-
ment 5 squarish, anterior margin with 1 cluster of long
spines; segment 6 little broadened, anterior margin with 1,
and posterior margin with 4, clusters of medium spines.
Pleopods, basis stout, broad, outer margin strongly
plumose-setose; outer ramus 15-segmented, inner 12-seg-
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995
40
FIG. 2 Eohaustorius eous (Gurjanova) Female ov. (6.0 mm). East coast Kamchatka peninsula.
(after Gurjanova, 1962)
merited. Pleon plate 3, hind comer strongly produced, nearly
straight, acute. Uropod 1, peduncle, outer margin with 4-
5 slender spines; inner ramus, posterior margin with short
spines. Uropod 3, outer ramus, terminal segment short (<1/
2 proximal segment); inner ramus, inner margin with 3
plumose setae.
Telson lobes short, slender, with 12 dorso-distal setae.
from the northern Sea of Okhtosk, illustrated in Guijanova
(loc. cit., fig. 1 36B2) is here considered a variant on the main
theme from the Kamchatka pensinsula andBering Searegions.
Eohaustorius estuarius Bos worth
(Figs. 4)
Distribution. Eastern Kamchatka & Bering Sea, 20-40
m; western Bering Sea, subtidally to 25 m. Not taken in
southeastern Alaska despite apparently suitable habitat (e.g. ,
Glacier Bay) where E. washingtonianus was dominant.
Eohaustorius estuarius Bosworth, 1973: 253, fig. 2 im. —
Staude, 1987: 372 (key), 383 , fig. 18.11 .—Barnard & Kara-
man, 1991: 363.
Material examined. 10 lots containing 158 specimens:
BRITISH COLUMBIA.
Taxonomic commentary. E. eous is a relatively primi-
tive species, showing several plesiomorphic character states
in common with the N. America estarine species E. estuarius.
It is not closely related to E. robustus, differing in the
character states noted in the key and on p. 37. The material
Queen Charlotte Islands, ELB Stns., July-Aug., 1957 (~10
specimens at 3 stations, verified by W. Bosworth, 1973):
H8a (Delkatla Slough) - 3 females; HIO (New Masset) - 1
female; W 1 (north end Lepas Bay) - 8 males 1 2 females, 6 im.
Vancouver I., northend, ELB Stns., 1959: 012, AhousBay,
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 41
FIG. 3. Pseudohaustorius caroliniensis Bousfield. Female (7.6 mm), lateral view; mouthparts, telson
2. Haustorius canadensis Bousfield. Female (12.0 mm), mouthparts, telson. (after Bousfield, 1973).
Vargas I. - 3 males, 1 fern, 1 im; Stn. 013, Yarksis, Vargas
I. - 4 males, 5 females, 1 im.
Central Vancouver I., ELB Stns.,1955: PI, Clayoquot I. - 1
female, 1 im; P6a, southeast end Wickaninnish Bay - 1 1
males, 26 females. ELB Stns., July, 1970: P701, south end
Long Beach, in surf-exposed sand at freshwater beach seep,
LW level - 1 female ov. (5.0 mm), (slide mount) (fig’d
specimen), + 17 males, 33 females, CMN Cat. no.
NMCC 199 1-1229; P708, Pachena Bay, mouth of estuary -
numerous specimens.
WASHINGTON. OREGON.
ELB Stn. W34, Crescent Beach, east end, near creek mouth-
1 female (4.8 mm), slide mount, -i-12 other females, 5 males,
CMN Cat. no. NMCC- 1992- 1255; Stn. W41. Sooes estuary,
near mouth, in steep sand banks - 1 im.
Diagnosis. Female (5.0 mm): Head, rostrum medium;
eyes small, weakly pigmented. Antenna 1, peduncle 2,
anterior margin setose nearly to base. Antenna 2, peduncular
segment 4, postero-distal lobe large, posterior margin with
25+ plumose setae; segment 5 distally broadest; flagellar
segment 1 with distal plumose seta.
Mandible, palp segment 3 , inner (posterior) margin with
10-12 marginal comb spines, outer margin with 5-6 mediums
etae. Maxilla 2, inner plate with strong facial row of setae.
Maxilliped, inner plate tall, slender; outer plate broad, distally
truncate; palp segment 2, inner lobe long narrow, reaching
tip of broadly expanded palp segment 3.
Gnathopod 1, basis, anterior margin weakly setose
throughout; carpus short, deep; dactyl, nail long. Gnathopod
2, carpus relatively short and deep, with sub-apical postero-
distal cluster of slender spines.
Peraeopod 3, coxae expanded anteriorly, basis with
antero-distal cluster of setae. Peraeopod 4, segment 4 with
2 posterior marginal plumose setae; segment 5, hind lobe
medium, proximal margin with a few setae, anterior margin
with strong oblique spine row, hind margin truncate, spinose;
segment 6 medium, little broadened distally, with single
oblique anterior marginal spine group.
Peraeopod 5, coxal hind margin strongly setose; basis
medium, hind margin proximally setose; segment 4 rela-
tively short, broad, facial spine groups strong; segment 5
shorter than broad, facial spines strong; segment 6 broadest
medially, with2 anterior marginal spine groups, hind margin
with single spine cluster. Peraeopod 6, basis medium, hind
margin distally bare; segment 4 relatively short, broadest
distally, with 4 weak facial groups of spines; segment 5
AMPHIPACMCA VOL. 11 NO. 1, AUG. 31, 1995 42
FIG, 4, Eohaustorius estuarius Bosworth, Female ov (5.0 mm) Long Beach, V. L, B. C.
(partly after Bosworth, 1973)
broader than deep, with 2 small facial clusters of spines, 3-
4 spines along inner distal margin, and 9-10 spines along
outer distal margin; segment 6 with 6-7 posterior marginal
clusters of short and long spines. Peraeopod 7, basis broadly
expanded, lacking proximal basal cusp, hind margin nearly
bare; segment 4 short, very broad distally, anterior margin
with 2 spine clusters, posterior margin lined with plumose
setae throughout; segment 5 short, broader than deep, with 2
anterior marginal spine clusters; segment 6 broad, anterior
margin strongly convex with single cluster of strong spines,
posterior margin with 2 spine clusters.
Pleopods normal for the genus. Pleon plate 3, hind
comer strongly produced, straight, acute. Uropod 3 rami
relatively short, <2X peduncle; outer ramus medium; inner
ramus with few inner marginal seta.
Telson lobes medium broad, regularly setose.
Distribution. Common in freshwater intertidal seeps
and rills over open and/or protected sand beaches, from
Central California north through Oregon, Washington, and
British Columbia to Dixon Entrance; not yet taken in south-
eastern Alaska.
Taxonomic commentary. As noted elsewhere (p. 59),
this specis shows mainly plesiomorphic character states. It
is a member of the E. eous subgroup and similar to E.
gurjanovae of the Asiatic North Pacific region..
Eohaustorius subuUcolus Hirayama
(Fig. 5)
Eohaustorius subulicolaRiTSiy ama, 1985: 43, figs. 155-157.
Eohaustorius subulicolusBamaid&Karaman, 1991: 463. —
Ishimaru,1994: 64.
Diagnosis. Male (2.25 mm): Head, rostmm short, de-
curved. Pigmented eyes lacking. Antenna 1, accessory flag-
ellum medially inserted on peduncular segment 3. Antenna
2, peduncular segment 4, antero-distal lobe shallow; hind
margin with few (~17) plumose setae; segment 5 of medium
width; flagellar segment 1 with single large postero-distal
seta.
Mandibular palp, segment 3 with few (4-5) comb spines.
Maxilla 1, outer plate with 8 apical spines. Maxilla 2, inner
plate with 6-7 submarginal facial row of setae. Maxilliped,
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 43
FIG. 5. Eohaustorius subulicolus Hirayama. Male
palp segment 3 narrowly clavate; outer plate narrow.
Coxa 1 vestigial; coxa 2 small rounded below, hind mar-
gin with single seta. Gnathopod 1 , segment 5 short and deep;
segment 5 slender. Gnathopod 2, basis with ~5 hind mar-
ginal setae; segment 5 with 5 distally spoon-shaped spines.
Peraeopod 3, basis, hind margin with distal setae only;
segment 5, hind margin lacking proximal setae; segment 6
narrow. Peraeopod 4, coxa slender smoothly convex in
front; basis hind margin bare; segment 4 with 4 posterior
marginal setae; segment 5 (carpus), posterior lobe slender
acute, lacking spines; segment 6 slender, with apical spine(s)
only.
Peraeopod 5, basis, posterior margin setose throughout;
segment 4 narrow, longer than broad, facial spines medium;
segment 5 slender; segment 6 slender, with single anterior
marginal spine. Peraeopod 6, basis, hind margin setose
throughout; segment 4 little broadened, facial spines lack-
ing; segment 5 broadest distally, lacking facial spines, distal
margin with a few spines near hinge; segment 6, postero-
distally with slender split-tipped spines and long setae. Per-
aeopod 7, basis lacking proximal cusp, hind margin straight.
(2.25 mm). Tomioka Bay. (after Hirayama, 1985).
nearly bare; segment 4 slender, hind margin nearly bare;
segment 5 as long as broad, anterior margin with 3-4 slender
spine groups; segment 6 slender with single anterior mar-
ginal spine cluster and elongate pectinate apical spines.
Pleopods, peduncle small; rami slender, outer ramus 9-
10-segmented. Pleon plate 3, hind corner strongly produced,
hooklike, extending well beyond postero-dorsal process.
Uropod 1, rami with apical spines and setae. Uropod 3, rami
slender; inner ramus lacking inner marginal setae; outer
ramus, terminal segment strong (> 2/3 inner segment).
Telson lobes slender, marginal setae few.
Distribution. Tomioka Bay, Japan; subtidal.
Taxonomic commentary. Eohaustorius subulicolus is
distinctive on the basis of reduction of some character states,
and special development of others. Hirayama (1985) des-
cribed the species from the type male and four additional
specimens. He noted its general resemblance to F. cheliferus.
but E. subulicolus may qualify for separate subgeneric
status.
AMPHIPACMCA VOL. 11 NO. 1, AUG. 31, 1995 44
Eohaustorius sawyeri, Bos worth
(Fig. 6)
Eohaustorius sawyeri Bosworth, 1973: 257, fig. la-e. —
Austin, 1985: 607. — Staude, 1987: 383, 372 (key). — Barnard
& Karaman, 1991: 363.
Material examined. Six lots containing 37 specimens
(both sexes and subadults), from 4 localities in British Col-
umbia, and two in California:
BRITISH COLUMBIA.
Vancouver I., southern end: Off Long Beach, V. I., 22 m, P.
Slattery Stn., 1982 - 3 males, CMN Cat. no. NMCC1991-
1219. ELB Stn. P21a, Trevor Channel, off Bordelais I., 44
m, fine sand, Aug. 9, 1975 - 1 female (3.2 mm) (slide mount)
(figured specimen) , CMN Cat. no . NMCC 1991-1227; Ibid . ,
Stn. B9c, off Second beach, 20-25 m, medium sand, June 28,
1976 - 1 female; ELB Stn. H41, Jordan R., black silty sand,
LW, July 27, 1964 - female ov (5.2 mm).
CALIFORNIA
Off Marine Laboratory, Moss Landing, 2 m sand, P. Slattery
coll., June 1, 1982 - 2 males, 7 females, CMN Cat. no.
NMCC1991-i240; Ibiil. 12 m, July 1, 1982 - 5 males, 8
females, CMN Cat. no. NMC1991-1239.
Diagnosis. Female im. (3.2 mm.): Head, rostrum. Eyes
whitish, not pigmented. Antenna 1, peduncle 2, anterior
margin weakly setose, singly inserted. Antenna 2, peduncle
4, postero-distal lobe medium, posterior margin with 30+
plumose setae, antero-distal lobe strong, extending >2/3
length of segment 5; segment 5 relatively shallow; basal
flagellar segment with 3-4 distal plumose seta.
Mandible, palp segment 3 with 8-11 posterior marginal
comb spines. Maxilla 1, palp stout, proximal segment short
(< 1/2 segment 2). Maxilla 2, inner plate, facial setae submar-
ginal. Maxilliped, outer plate medium; palp segment 2, inner
lobe narrow, shorter than medium-large segment 3.
Gnathopod 1, coxa subquadrate; basis broadened medi-
ally, anterior margin smooth distally; segment 5 elongate,
medium deep; segment 6, thick (deep). Gnathopod 2, basis,
anterior margin smooth; segment 5 slender, lower margin
straight.
Peraeopod 3, coxa 3 subquadrate; segment 4 short, very
broad distally; segment 5 deep, with antero-proximal in-
vagination, hind margin proximally setose; segment 6 large,
lozenge-shaped, margins slender- spinose. Peraeopod 4, seg-
ment 4 with 4 postero-marginal setae; anterior margin with
distal spine group; segment 5, anterior margin with fan- wise
spine row, hind lobe short, postero-proximal margin with 2
spine clusters; segment 6 stout, broadening distally, with 2
anterior and 2 posterior marginal spine clusters.
Peraeopod 5, basis broadly ovate, hind margin nearly
bare distally; segment 4 short, strongly broadest distally,
facial spines strong; segment 5 expanding distally, longer
than broad, facial spines strong; segment 6 broad, apex
truncate, anterior margin with 1, posterior margin with 3
spine clusters. Peraeopod 6, basis medium broad, hind
margin lightly setose proximally; segment 4 long, broadest
distally, with several strong facial spine clusters; segment 5
broadening distally, with 2 strong facial spine clusters antero-
distal margin with 12-15 spines, excavation shallow; seg-
ment 6 slender, with 4-5 posterior marginal spine clusters.
Peraeopod 7, posterior margin of coxa broadly acute; basis
broad, convex hind margin distally with a few short setae,
lacking proximal cusp; segment 4 short, broadest distally,
hind margin setose; segment 5 broader than deep, anterior
margin with single spine group, antero-distal free margin
broad, lined with spines, postero-distal angle with long
heavy spine; segment 6 broad, anterior margin with 1, post-
erior margin with 3-4 stout spine groups.
Pleopods, peduncle short broad, outer margin strongly
plumose- setose; outer ramus 16-segmented, inner ramus 13-
segmented. Pleon plate 3, hind corner moderately produced,
acute, strongly overhung by, and much shorter than, postero-
dorsal process of pleosome 3. Uropod 1, peduncle, outer
margin with 3-4 slender spines, distal spine cluster medium;
inner ramus posteriorly setose; outer ramus narrow, apex
sub-acute. Uropod 3, outer ramus slightly the longer, terminal
segment medium; inner ramus lacking inner marginal setae.
Telson lobes short, broad, with few dorso-distal setae.
Distribution. A southern species, abundant along coasts
of California and Oregon, diminishing in Washington, and
barely entering British Columbia. Occurs along outer surf-
exposed sand beaches, from MLW to shallow subtidally.
Taxonomic Commentary. The large female specimen
from Jordan R. exhibited a very broad segment 6, and heavy
facial spines on segments 4 & 5 of peraeopods 5 and 6.
Eohaustorius sencillus J. L. Barnard
(Fig. 7)
Eohaustorius sencillus Barnard, 1962: 249, figs 1, 2. — Bos-
worth, 1973: 8 (key). — Barnard, 1975, fig. 44. — Barnard &
Karaman, 1891: 363.
Material examined. Mile buoy, off Moss Landing,
California, 20 m sand, P. Slattery coll., Feb. 24, 1971 - 1
female (slide mount) (figured specimen), CMN Cat. no.
NMCC1991-1241; 13 additional females, 2 males.
Diagnosis. Female (3.5 mm): Head, rostrum short.
Pigmented eyes lacking. Antenna 1 , peduncular segment 2,
anterior margin weakly setose, bare proximally. Antenna 2,
peduncular segment 4 relatively short and deep, postero-
distal lobe medium, hind margin with 25-30 plumose setae;
segment 5 as deep as long; basal flagellar segment postero-
distally with 4-5 long setae.
Mandible, palp segment 3 slender, with 7 posterior
marginal comb spines. Maxillae undescribed. Maxilliped,
outer plate broad; palp segment 2, medial lobe large, broad,
shorter than moderately broadened terminal segment.
. AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 45
FIG, 6. Eohaustortus sawyeri Bosworth, 1973. Female ov ( 3.2 mm ). Off Long Beach, V.I., B.C.
Coxae 1 & 2 squarish below. Gnathopod 1 , basis with
7-8 posterior marginal setae; segment 5 medium, deep,
convex below; segment 6 sharply broadest medially; dactyl,
unguis large, heavy. Gnathopod 2, basis lined posteriorly
with longish setae; segment 5 slender, strongly setose;
postero-distal spines few, weak; segment 6 slender, regular.
Peraeopod 3, coxa deep, sublunate; segment 4 medium
broad distally, hind margin with 7-9 setae; segment 5 rela-
tively shallow, anterior margin bare, not emarginate proxi-
mally, lower margin proximally setose; segment 6 lenticular.
margins slender spinose. Peraeopod 4, segment 4 relatively
large, hind margin convex, with 2-3 long setae, anterior
margin with weak oblique spine row; segment 5, with weak
anterior oblique spine row, posterior lobe medium, rounded
behind, with 2 weak postero-proximal spine groups; seg-
ment 6 slender, with anterior marginal spine cluster, and 2
postero-distal single marginal spines.
Peraeopod 5, basis ovate, hind margin lacking distal
setae; segment 4 not broader than deep, parallel-sided, facial
spine groups weak; segment 4 relatively small, not wider
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 46
FIG 7. Eohaustonus sen ciUus Barnard, 1962. Female (3.5 mm). Off Moss La nding, California.
than deep facial spine groups weak; segm ent 6 not br^- Pleon plate 3. hind comer acutely produced, short Up
ened, anterior and posterior margins each with 2 single directly beneath dorsal we^ Tne;
snines anex narrowly truncate, weakly spinose. outer margin nearly bare, distal spine cluster weak, inner
Peraeopodb coxa narrow, deep; basis relatively little broad- ramuswealdysetosepostenorly;outerramus,postenormM-
Ined h^d margin with proxLal setae only; segment 4 gin with slender spines. Uropod 3 rami ^
donaate broadest medially, with 6 small facial spine clus- -2X peduncle; outerramus,ternmn^ segment very short (<U
2rs segment 5 not broadL than deep, with single facial 3 proximal segment); innerrarnus, ^nd margin
Se anXdistalmarginwith4-5spines,excavationdeep; Telson lobes short, broad, with 6-8 dorso-distal setae.
4 longer than broad, gently broadening distally, anterior not reaching Canadian waters.
margin with 2 spine clusters, hind margin with 5 plumose
setae; segment 6 slightly broader than deep, with anterior
spine cluster; anterior distal free margin relatively short;
segment 6 medium broad, anterior margin with 1 , posterior
margin with 3-4 spine clusters, apex truncate, spinose.
Taxonomic Commentary. This species is distinguished
by the relatively large basis of peraeopod 7, and large dactyl
of gnathopod 1. Bosworth (pers. communic.) recognized a
variant in deeper water material of J. L. Barnard (loc. cit.).
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995
47
FIG. 8. Eohaustorius gurjanovae, new species. Female ov (6.Q mm). Southern Sakhalin I., Sea of Japan.
(modified from Gurjanova, 1962)
Eohaustorius gurjanovae^ new species
(Fig. 8)
Eohaustorius washingtonianus Gurjanova, 1962: 404, figs
135B, V.
Type material. Female ov (6.0 mm), Holotype; 7
females and males, Paratypes, from south coast of Sakhalin
I., Sea of Japan; collections of the Zoological Museum, St.
Petersburg, Russia.
Diagnosis. Female (7.0mm): Head, rostrum short; pig-
mented eyes lacking. Antenna 1 , peduncle 2 anteriorly setose
throughout. Antenna 2, peduncular segment 4, posterior
margin with 25-30 plumose setae; postero-distal lobe large,
extending to mid-point of deep segment 5; basal flagellar
segment with 1 stout postero-distal plumose seta.
Mandibular palp medium, with 7-8 posterior marginal
comb-spines. Maxillae 1 & 2 undescribed. Maxilliped, outer
plate slender, tall; palp segment 2, inner lobe slender, long,
nearly reaching tip of clavate palp segment 3.
Gnathopod 1, coxa, hind comer squarish; dactyl, body
palm-shaped, unguis large. Gnathopod 2, basis, posterior
margin lined with medium setae; segment 5 slender, postero-
distal spine cluster strong; segment 6 much shorter, slender.
Peraeopod 3, coxa, anterior margin rounded; basis thick,
heavy; segment 4 short, expanding to broad distal margin,
antero-distal angle and posterior margin with several plumose
setae. Peraeopod 4, coxa subquadrate, lower and hind marg-
ins setose; basis with a few postero-distal setae; segment 4,
hind margin with 3-4 plumose setae, anterior margin with
medial cluster of slender spines; segment 5 hind lobe short,
anterior margin with oblique row of stout spines, postero-
proximal margin with 2 groups of stout spines; segment 6
short, broadening distally to large apical cluster of spines,
anterior margin with single spine cluster and a few setae.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 48
Peraeopod 5, basis broad, orbicular, hind margin devoid
of setae except proximally and mid-distally; segment 4
broadening gradually, longer than wide, with clusters of
stout facial spines; segment 5 smaller and narrower, facial
spines strong; segment 6 broad, anterior margin with 2
clusters of stout spines, posterior margin with 2 singly
inserted spines, apical spines strong. Peraeopod 6, basis
medium broad, hind margin setose throughout, except for
short distal gap; segment 4 short, very broad, with 2 anterior
clusters and 1 posterior submarginal row of stout spines;
segment 5 much broader than deep, with 2 facial spine
clusters, and 6-7 antero-distal marginal spines, distal exca-
vation medium deep; segment 6 large, bent forward, hind
margin with 6 clusters of spines, some elongate distally.
Peraeopod 7, basis very broad, hind margin with 4-5 medio-
distal setae and blunt proximal cusp; segment 4 broadly
triangular, anterior margin with 2 spine clusters, hind margin
setose throughout; segment 5 large, slightly broader than
segment 4, anterior margin with 2 spine clusters, antero-
distal free margin heavily spinose, postero-distally angle
with medium stout spine; segment 6 medium, anterior mar-
gin with 3-4, and posterior margin with 3, spine clusters,
some spines elongate, apex broad, heavily spinose. Long
anterior marginal spines are split-tipped or clavate.
Pleon plate 3, hind comer normally produced, acute, not
elongate, with several lower marginal and submarginal
plumose setae. Uropod 1, peduncle, outer margin weakly or
not spinose; outer ramus, posterior margin with subapical
fan of spines; inner ramus, posterior margin distally with
long setae. Uropod 2, peduncle and rami regularly setose.
Uropod 3, rami subequal, shorter than 2X peduncle; terminal
segment of outer ramus short; inner ramus with 4-5 inner
marginal setae. Telson lobes slender, each with 5-6 dorso-
distal plumose setae and several inner marginal fine setae.
Etymology. The species is named in honour of the late
Eupraxie F. Guijanova who first recorded and figured the
material from the Soviet far eastern region, as reproduced
here.
Distribution. South coast of southern Sakhalin I., Sea
of Japan, in sand at 19 m. depth.
Taxonomic commentary. E. guijanovae is another
member of the advanced group of species including E. rob-
ustus, E. cheliferus and E. washingtonianus. As noted by Dr
Gurjanova (loc. cit., p. 405), this species differs from the
North American Pacific species, E. washingtonianus, in a
number of morphological character states, including the
stronger armature of peraeopods 5-7, the more numerous
carpal spines of gnathopod 2, and the linear setose lobes of
the telson. Together these two forms do not qualify as a pan-
Pacific sibling species pair and are here considered distinctly
separate species.
Eohaustorius robustus (Gurjanova) new status
(Fig. 9)
Haustorius eous robustus Guijanova, 1953:216.
Eohaustorius robustus eous Guijanova, 1962:409. — Barnard
& Karaman: 363.
Material examined. No specimens were taken in the
North American study region.
Diagnosis. Female (6.5 mm): Head, rostrum short. Pig-
mented eyes lacking. Antenna 1 , flagellum short, peduncular
segment 2 with thick, coarse, facial plumose seta distally.
Antenna 2, peduncular segment 4 short and deep, hind
margin with -35 plumose setae; postero-distal lobe large;
segment 5 deepest mid-distally; basal flagellar segment
postero-distally with 3 short plumose setae.
Mandibular palp, segment 3 relatively broad, shorter
than 2 relatively, with 7 posterior marginal comb spines.
Maxillae and maxillipeds not described or figured.
Coxae 1 & 2 small, regular. Gnathopod 1 , basis, hind
margin sparsely setose; segment 5 large, deep, strongly
setose behind; segment 6 short broad; dactyl with long
straight unguis. Gnathopod 2, basis, hind margin with
several long setae; segment 5 elongate, postero-distal spines
numerous, short, apically spoon-shaped; segment 6 short,
apically narrowing abruptly.
Peraeopod 3, coxa rectangular, basis, hind margin setose
throughout; segment 4 broadening gently distally, hind mar-
gin setose throughout; segment 5, anterior margin with
proximal excavation or notch, hind margin proximally with
plumose setae; segment 6 lenticular, marginal spines strong.
Peraeopod 4, coxa rounded anteriorly, with squared hind
comer; basis with antero- and postero-distal clusters of setae;
segment 4, hind margin with 5 setae, 3 longish; segment 5,
anterior margin with single setal cluster, hind lobe medium,
antero-distal spine cluster strong, distal margin bare; seg-
ment 6 small, short, with hind margin and apical spine
clusters.
Peraeopod 5, coxa deep, hind margin strongly setose;
basis asymmetrically broad, hind margin distally bare; seg-
ment 4 broadening distally, with strong marginal and facial
spine clusters, and strong postero-distal setal cluster; seg-
ment 5 narrower, squarish, with stout spine clusters; segment
6 medium, with 1 anterior marginal spine cluster, and a few
posterior marginal and apical spines. Peraeopod 6, basis
relatively short and very broad, broadest distally, hind mar-
gin short-setose; basis large, broadening distally, with strong
anterior facial clusters and posterior facial row of spines;
segment 5 broadest distally with 2 strong anterior facial spine
clusters; antero-distal margin with 9-10 spines, excavation
deep; segment 6 large, bent forward, hind margin with 5
spine clusters, some distal spines elongate, tips funnel shaped,
notched. Peraeopod 7, basis very broad, proximally truncate
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995
49
FIG. 9. Eohaustorius robustus (Gurjanova). Female (7.0 mm). Greater Kurile Islands.
(modified from Gurjanova, 1962).
behind, margin smooth; segment 4 short, very broad, hind
lobe narrow, with apical cluster of plumose setae; segment 6
short, very broad, with 2-3 anterior marginal, and 3 posterior
marginal spine groups . Longest anterior marginal spines of
segments 4-6 are club- or funnel-tipped.
Pleon side plate 3 with a few facial and submarginal
plumose setae; hind corner moderately produced, acute,
apex upturned slightly. Uropod 1, rami and peduncle
subequal, both rami with distally hooked apical spines; outer
ramus with weak subapical setae, inner ramus, posterior
margin with 3 groups of long setae. Uropod 2 rami shorter
than peduncle, normally setose. Uropod 3, rami short, less
than 2X peduncle; terminal segment of outer ramus very
short (1/4 proximal segment); inner ramus, inner margin
with 5-6 stout plumose setae.
Telson lobes medium, narrowing distally, with about 7
dorso-distal setae.
Distribution. Pacific coast of the Large Kurile Island
chain (Paramushir, Iterup Islands), and sublittoral of the
northwestern Sea of Okhotsk, at depths of 10-40 m.
Taxonomic commentary. Another species of the ad-
vanced subgroup (including £. cheliferus), but distinguished
by characters given in the key (p. 37). It is not at all closely
related to E. eous, from which it is distinguished by a
combination of 3-4 species level character states. E. rob-
ustus is superficially close to E. gurjanovae in several char-
acter states of peraeopods 5-7.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995
50
Eohaustorius brevicuspis, Bosworth
(Fig. 10)
Eohaustorius brevicuspis Bosworth, 1973: 255, figs. 1-3.
—Austin, 1985: 605.— Staude, 1987; 383, 372 (key).—
Barnard & Karaman, 1991; 363.
Material examined. 4 lots containing 20 specimens,
none from British Columbia.
WASHINGTON.
ELB Stn W39, Neah Bay, Clallam Co., medium sand at LW,
July 30, 1966 - 3 males, 2 females, 1 im. NMCC1991-1233;
ELB Stn. W46, Leadbetter Pt., Pacific Co., surf exposed sand
atLW, Aug. 4, 1966 - 4 males, 2 females, NMCC 199 1-1236.
OREGON.
ELB Stn. W58, Seal Rock, Lincoln Co., LW surf sand, Aug.
13, 1966 - 1 female ov (4.5 mm) (slide mount) (figured
speci-men), 1 female ov (4.6 mm) slide mount, CMN Cat.
no. NMCC 199 1-1237; 4 males, 5 imm.
CALIFORNIA.
ELB Stn. Cl, Crescent City, surf sand beach at LW - 1
subadult female, NMCC 199 1-2094.
Diagnosis. Female ov(4.0 mm): Head, rostrum short,
blunt, not exceeding antero-lateral head lobes. Eyes small
ovate, adjacent to anterior margin, whitish, lacking pigment.
Antenna 1, peduncular segment 2 with strong anterior mar-
ginal clusters of setae. Antenna 2, peduncular segment 4
short, medium deep, hind margin with relatively few ( 1 8-20)
plumose setae, postero-distal lobe short; segment 5 little
broadened distally.
Mandible, palp segment 3 medium long, with 12 poste-
rior marginal cohib spines. Maxilla 1 & 2?? Maxilliped,
outer plate medium; palp segment 2, inner lobe relatively
small, distinctly exceeded by broadly expanded palp seg-
ment 3.
Coxa 1?, coxa 2 rounded below. Gnathopod 1, basis,
anterior margin proximally with short setae, posterior mar-
gin distally with a few long setae; segment 5 long, deep;
segment 6 short, distally slightly broadening. Gnathopod 2,
basis, anterior margin medially setose, posterior margin with
a few longish setae; segment 4 slender, shallow; segment 6
short, not medially broadened.
Peraeopod 3, basis, anterior and posterior margins distally
with a few long setae; basis medium broad distally, hind
margin sparsely plumose-setose, segment 5 shallow, with
postero-proximal marginal setae; segment 6 small, lenticu-
lar, margins spinose. Peraeopod 4, coxa very broad, lower
margin nearly straight; segment 4, anterior margin with 2
small groups of setae, hind margin with pair of long plumose
setae; segment 5, anterior marginal oblique spine row strong,
posterior lobe medium, hind margin proximally with a few
spines and setae, distal margin with weak spine cluster;
segment 6 medium, anterior margin with 2 weak clusters of
spines and setae, hind margin distally to apex with a few
longish setae and medium spines.
Peraeopod 5, coxa shallow, hind lobe, lower margin
setose; basis broader than deep, hind margin setose through-
out; segment 4 slightly broadening distaUy, anterior clusters
and posterior rows of facial spines strong; segments slightly
narrower, facial spines strong; segment 6 medium, with 2
anterior marginal spine clusters, posterior margin with single
spines. Peraeopod 6, basis broadening distally, with large
postero-distal lobe, hind margin setose proximally; segment
4 very broad distally, with 2 weak facial spine groups;
segment 5 short, very broad with 1 posterior and 2 anterior
submarginal facial spine groups, distal margin with 6-7
spines, distal excavation medium; segment 6, short, thick,
posterior margin with 6-7 spine clusters, long spines split-
tipped. Peraeopod 7, basis very broad, suborbicular, hind
margin nearly bare, with broadly rounded proximal cusp;
segment 4 short very broad distally, anterior margin with 3
spine clusters, posterior margin with a few plumose setae
distally; segment 5 narrower, but wider than long, anterior
margin with 2-3 spine clusters, postero-distal comer with
short to medium spines; segment 6 broad, with 1 anterior and
2 posterior marginal spine clusters and long spines at tmn-
cate apex.
Pleon plate 3 , hind comer moderately strongly produced,
tip acute, not upturned. Uropod 1 , peduncle, outer margin
with a few distal spines and apical cluster of 3 heavy spines;
rami with strong apical spine clusters; inner ramus with
several long posterior marginal setae and a medio-distal
cluster of spines; outer ramus with a few posterior marginal
spines; uropod 3, rami subequal, ~'2X peduncle, terminal
segment of outer ramus medium; inner ramus, inner margin
with 3-4 plumose setae.
Telson lobes short, thick, with 7-8 dorsal distal setae and
several inner marginal setae.
Distribution. Central California north to the Strait of
Juan de Fuca, in clean medium sand of surf exposed high
salinity beaches, MW level to immediate subtidal depths.
Taxonomic commentary. E. brevicuspis is closely
similar to the intertidal species washingtonianus, overlap-
ing it distributionally in the Oregon- Washington region, and
replacing it further south.
Eohaustorius washingtonianus (Thorsteinson)
(Figs. 11, 12)
Haustorius washingtonianus Thorsteinson, 1941:61, figs.
39-51.
Eohaustorius washingtonianus J.L. Barnard, 1957: 81 (part).
— Barnard, 1962: 249 (key). — Bosworth, 1973: 8 (key), fig.
E.— Austin, 1985: 607.— Staude, 1987: 383, 372 (key).—
Barnard & Karaman 1991: 363.
non : Eohaustorius washinstonianus Barnard, 1957: PI. 16.
— Gurjanova, 1962: fig. 135A.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 51
FIG. 10. Eohaustorius brevicuspis Bosworth,
Material examined. About 55 lots containing approx.
600 specimens, of all sexes and life stages (except very
juvenile), as follows (numbers of specimens in parentheses):
SOUTHEASTERN ALASKA.
Prince William Sound to Alexander Archipelago, ELB stns . ,
June-Aug., 1961, LW and shallow sub-tidal levels - A54 (3);
A71 (1); A81 (30); A83 (1); A121 (1); A140 (1). ELB Stns,
July 28 - Aug. 4, 1980: S4B1 (l);S4B2(f.w. stream outflow)
(2); S11B3 (15); S16B1 (1); S16B4 (2); S19B1 (2); S16B4
BRITISH COLUMBIA.
Queen Charlotte Islands, ELB Stns, July- August 1957- H3
(1); H8a (2); H13 (29); H14 (17); El (12); E14b (31); E17
(4); E21 (1); W2 (44).
North-central mainland coast, ELB Stns, July, 1964: HI (3);
HIO (1 1): H23 (48); H39 (15); H48 (32); H50 (49); H59 (3).
1973. Female ov (4. 5 mm). Seal Rock, O regon.
Northern Vancouver I. & adjacent mainland; ELB Stns
1959: N1 (15); N6 (16); 013 (1).
Central Vancouver I., ELB Stns 1975; P28 (48); P29 (1).
Southern Vancouver L, ELB Stns., 1955: F4, Albert Head,
near Victoria (2); F5 (9); P6a (8); P8 (4). ELB Stns., July,’
1970: P703 (4); P708 (22); P711 (17); P716 (5); P17 (1).
ELB Stns., 1964: H41 (16); H42 (16); H43 (79); H45 (25).
ELB Stns., 1975: Plc(15); Plb (46). ELB Stns., 1976: B 12a
(2); ELB Stns, 1977: B5a, Witty’s lagoon - 1 female ov (7.0
mm), female ov (5.0 mm), male (5.0 mm) (slide mounts), -i-
14 additional females, CMN Cat. no. NMCC1991-2107-
B5c (51).
Southern mainland, ELB Stns., 1955: Mil, White Rock
( 10 ).
WASHINGTON
ELB stations, 1966: W34, Crescent Beach, LW sand (with£
estuarius) - 10 males, 19 females, 5 im.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 52
Diagnosis. Female (5.0 mm): Head, rostrum short. Eyes
small, lenticular, whitish, lacking pigment. Antenna 1,
segment 2 with strong anterior marginal setae, lacking
proximally. Antenna 2, segment 4 medium deep, hind
margin with ~25 plumose setae, postero-distal lobe medium;
segment 5 large, medium broad; flagellar segment 1 with
single postero-distal plumose seta.
Mandible, palp segment 3 medium, with 11-12 posterior
marginal comb spines. Maxilla 1, palp segment 1 short.
Maxilla 2, inner plate with inner marginal setae only.
Maxilliped, inner plate and outer plates broad; palp segment
2, medial lobe broad, not attaining tip of moderately broad-
ened segment 3.
Coxa 1, and 2 small, squarish. Gnathopod 1, basis with
few distal posterior marginal setae; segment 5 medium deep;
segment 6 broadening distally. Gnathopod 2, basis with
postero-distal marginal setae; carpus slender, elongate,
postero-distal spines slender; segment 6 short, medially
broadest.
Peraeopod 3, basis medium, hind margin with distal
setae; segment 4 long, gently broadening distally; segment 5
medium deep, anterior margin with shallow proximal exca-
vation, hind margin proximally with setae; segment 6 drop-
shaped, margins slender-spinose. Peraeopod 4, segment 6,
hind margin with 2-3 long plumose setae; segment 4 with
strong anterior marginal oblique row of spines, hind lobe
medium, with 2 postero-proximal, and 1 distal, spine cluster;
segment 6 slender, with 2 anterior groups of spines and setae,
and hind margin distally with single spines and setae.
Peraeopod 5, coxa, hind lobe deep, margin weakly setose;
basis short broad, suborbicular, hind margin setose except
distally; segment 4 short, broadest distally, With moderate
anterior clusters and posterior rows of facial spines; segment
5 longer than wide, facial spines strong; segment 6 slender,
with 2 anterior marginal and 3 posterior marginal clusters of
slender spines and setae, apex slender-spinose. Peraeopod 6,
coxa deep, hind lobe setose below; basis broad, with shallow
distal lobe, hind margin setose proximally ; segment 4 medium
long, broadest distally, with 2 weak facial spine clusters;
segment 5 broadest distally, with 2 medium posterior facial
clusters of spines and distal marginal row of 8-10 spines,
distal excavation medium; segment 6 medium, nearly straight,
hind margin with 5-6 clusters of spines, a few distal spines
long, split-tipped. Peraeopod 7, basis broad, suborbicular,
hind margin nearly bare, with strong proximal cusp or tooth;
segment 4 medium, widest distally, hind margin setose
throughout; segment 5, anterior margin with 2 clusters of
spines, tips clavate, distal free margin with small spine
cluster; segment 6 medium broad, with 1 antero-marginal
and 2 postero-marginal clusters of spines.
Pleon plate 3, hind comer weakly produced, acute, well
exceeded by postero-dorsal pleosomal lobe. Uropod 1,
peduncle with a few weak marginal spines, distally with 3-
4 stout spines; rami subequal; inner ramus, posterior margin
setose; outer ramus posteriorly with singly inserted and
clusters of spines and setae. Uropod 3, outer ramus, terminal
segment medium; inner ramus with 4-5 inner marginal
plumose setae. Telson lobes short, thick, with 5-6 dorso-
distal and 4-5 inner marginal setae.
Distribution: From Prince William Sound, Alaska,
southward along southeastern Alaska, British Columbia and
Washington to southern Oregon, possibly to central
California. It occurs bathymetrically from about mid-tide to
shallow sub-tidal levels, in fine sand, mainly along open,
surf-exposed beaches, but also on protected beaches; it co-
occurs with E. estuarius in salinities as low as - 10%o.
Taxonomic commentary: E. washingtonianus is the
type of a unique and moderately advanced N. American
endemic group of species. It contains 3 other N. American
endemic full species, as noted in the key, and a variety as
noted below. The group is typical of high energy intertidal
surf sands, but the subtidal members are less strongly ar-
moured. This species complex is most closely related to £.
eous group of western Pacific shores. As noted by Gurjan-
ova (1962), it bears some resemblance to, and possible direct
relationship with, E. gurjanovae (see histogram, p. 59).
Eohaustorius washingtonianus variant
Material examined.
BRITISH COLUMBIA.
North-central coast. ELB Stns., 1964: H48, Goose I., north
beach, fine sand at LW level, 9.8 C., Aug. 5-17 males, 14
females, 1 immature. ELB Stns., 1959: Nl, Open Bight,
Rivers Inlet, coarse sand atLW level, Aug. 3-15 im., CMN
Cat. no. NMCC 1991 -2095 ;N6,Bremner Beach, near Raynor
Pt., fine sand at LW level, 10.0 C., Aug. 6 - 7 males, 9
females.
Taxonomic commentary. Bos worth (personal com-
munication) briefly commented upon a somewhat anom-
alous feature of specimens of "washingtonianus" from the
three stations listed above. This observation is here con-
firmed. In peraeopod 7, segment 2 (basis) bears a small but
distinctpostero-proximal cusp, typical of £. washingtonianus,
£. brevicuspis and£. bamardi of N.orth American beaches,
and £. gurjanovae of western Pacific shores (p. 47). However,
the present variant resembles £. bamardi in having a single
group of spines (excluding the antero-distal group) on the
anterior margin of segment 5 of peraeopod 7. This northern
variant differs from £. bamardi in its other specific char-
acters (key, p. 37), but appears otherwise similar to material
of washingtonianus from adjacent northern localities. We
therefore conclude, tentatively, and on the basis of the
limited material available, that specimens from the three
stations above represent a local, mainly subtidal, variant of
the typical form of Eohaustorius washingtonianus
(Thorsteinson).
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 53
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 54
FIG. 12. Eohaustorius washingtonianus (Thorsteinson). Female (5.5 mm). Point Roberts, WA.
(after Thorsteinson, 1941).
Eohaustorius barnardi , new species
(Fig. 13)
Eohaustorius washingtonianus J. L. Barnard, 1957; 82, plate
16. — Bosworth, 1974 (letter and manuscript to ELB).
Material. The species occurred in samples from the
1956 and 1959 “Velero” cruises near Pt. Conception, and
further south, in depths of 5-20 meters (Barnard, loc. cit.).
The species was also collected by E. W. Fager from the
end of the Scripps’ s pier in 1955- 1956 (fide W. S. Bosworth).
Diagnosis. Female ov., Holotype (5.0 mm), 5 Paratype
specimens, ’’Velero" Stn. 2312-53, collections of the Allan
Hancock Foundation. Similar to Eohaustorius washington-
ianus, with the following differences:
Mandible, palp segment 3, posterior margin with 9-10
(vs. 1 1) comb spines, and distal spines of outer margin more
numerous (9-10 vs. 6-7). Maxilla 2, outer plate with 1 distal
outer marginal plumose seta. Maxilliped, outer plate shorter,
more slender; palp segment 3 less broadly expanded.
Gnathopod 1 , segment 5 more deeply broadened distally .
Gnathopod 2, basis, hind margin more heavily setose; seg-
ment 6 broadened distally.
Peraeopod 3, coxa, antero-distally angled, not rounded,
lower margin nearly straight. Peraeopod 4, coxal plate
subrectangular; segment 5, hind lobe short; segment 6 broad-
ened medially.
Peraeopod 5, coxa shallower, hind lobe more richly
setose behind; basis less broad; segment 6 relatively short
broad, margins and apex with fewer spines. Peraeopod 6,
basis broadening distally; segment 4 slightly narrowing
distally, facial spines few, weak; segment 5, facial spines
few, distal excavation more pronounced. Peraeopod 7, basis
with weaker proximal posterior cusp; segment 4 less broad
distally; segment 5, anterior margin with 1 cluster of spines.
Pleon plate 3, hind comer more strongly produced,
sharply acute, less exceeded by postero-dorsal process of
pleon 3. Uropod 3, rami more slender, inner ramus with
fewer inner marginal setae.
Taxonomic commentary. According to Bosworth
(1973; personal communication), Barnard (1957, plate 1)
incorrectly designated his subtidal material from southern
California as Eohaustorius washingtonianus, mainly be-
cause of the pronounced cusp on the basis of peraeopod 7.
However, Bosworth noted that the cusp is more strongly
pronounced, and the ratio of segments 5 & 6 of peraeopod 5
is different in Thorsteinson's original northern species.
Other differences, noted in this study, include (in E.
barnardi) the smaller size of maxilliped palp segment 3, the
smaller size of the carpal lobe of peraeopod 4, the weaker
facial armature of segments 4 & 5 of peraeopod 6, the less
prominent hind lobe of segment 4 of peraeopod 7, and the
more prominent and more strongly angled posterior process
of pleon plate 3.
Etymology. We take pleasure in formally naming this
species in honour of the late Dr J. L. (Jerry) Barnard who
intially described and figured it, and who contributed inesti-
mably to the advancement of knowledge of the systematics
and biogeography of fossorial amphipod crustaceans.
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 55
MX2 MX1
FIG. 13. Eohaustorius barnardi, new species. Female (5.0 mm). San Pedro shelf, --15 m, California.
(modified from Barnard. 1957L
Eohaustorius cheliferus (Bulycheva)
(Fig. 14)
Haustorius cheliferus Bulycheva, 1952: 198, fig. 3.
Eohaustorius heliferus Gurjanova 1962; 411, figs. 138 A, B.
Eohaustorius cheliferus Barnard & Karaman, 1991; 363. —
Ishimarus, 1994; 64.
Diagnosis: Female ov (7.0 mm) Head broad, rostrum
short, broadly acute. Eyes unpigmented. Antenna 2, pedun-
cle 4, posterior lobe large, with 35-t- marginal plumose setae,
postero-distal lobe strongly produced, attaining end of seg-
ment 5; segment 5 broadest medio-distally; flagellar seg-
ment 1 with 3 postero-distal plumose setae.
Mouthparts imdescribed.
Gnathopod 1, basis, hind margin weakly setose; seg-
ment 5 shallow, not elongate; segment 6 broadest medio-
distally, dactyl stout, unguis linear, longer than body.
Gnathopod 2, basis, posterior margin distally setose; seg-
ment 5 slender, postero-distal spines each with medial cross-
piece, distally toothed; segment 6 slender, short.
Peraeopod 3, coxa lunate, hind comer acute; basis
broad, margins distally setose; segment 4 medium, distally
broad, hind margin richly setose; segment 5 deep, hind
margin heavily setose; segment 6 drop-shaped, margins
lightly spinose. Peraeopod 4, segment 4, anterior oblique
row with stout spines, posterior margin with 3 long setae;
segment 5 with strong anterior oblique spine row, posterior
lobe large, long, postero-proximal margin with 4 clusters of
spines and long setae, distal free margin bare; segment 6
small, overhung by lobe of 5, with single anterior marginal
spine cluster, posterior marginal spines continuous with
apical spines.
Peraeopod 5, basis broadening distally, postero-distal
lobe faint, hind margin fully setose; segment 4 long, little
broadened, facial spine rows strong; segment 5 subquadrate,
facial spines strong; segment 6 medium, with single anterior
and posterior marginal spine groups. Peraeopod 6, basis
broad, hind margin strongly convex, setose proximally;
segment 4 medium, broadest subapically, with 4-5 clusters
of facial spines; segment 5 slightly broader distally, with
single facial spine cluster, distal free margin with 7-8 spines,
distal excavation medium deep; segment 6 short, curved
forwards, hind margin with longish simple-tipped spines.
Peraeopod 7, basis broad, hind margin nearly straight, distally
weakly setose, lacking proximal cusp; segment 6 triangular,
broadest distally, hind margin setose; segment 5 longer than
broad, anterior margin with 2-3 spine clusters, distal free
margin short; segment 6 medium broad, anterior margin with
1, posterior margin with 2, spine clusters
Pleon plate 3, hind comer acute, produced, apex acute
slightly angled upwards; lower margin setose. Uropod 3,
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 56
FIG. 14. Eohaustorius cheliferus (Bulycheva). Female ov (7.0 mm). Japan Sea to Sea of Okhotsk.
(modified from Bulycheva, 1952)
rami medium; terminal segment of outer ramus medium;
inner ramus, inner margin with 4-5 plumose setae. Telson
lobes elongate, narrowly oval, with long dorso-distal setae.
Distributional commentary. Pacific coast of Iturup I,
30-40 m depth. Also recorded from the Sea of Japan (Peter
the Great Bay) in depths of 0.75-13 m; also Sea of Okhotsk
(Amur R. estuary and Aniv Bay) and Southern Kurile Strait,
in depths of 6 - 40 m (Gurjanova, 1962).
Taxonomic commentary. The illustrations of Buly-
cheva (1952), repeated in Guijanova (1962), are limited in
detail but, in conjunction with her descriptive text, provide
sufficient basis for reliable separation as a species distinct
from all others of this study. As noted in the phenogram (p.
59) the species bears similarities to E. longicarpus of South
Korean waters, and to E. sencillus of the North American
Pacific coast, but is otherwise distinct from nearly every-
thing else.
This species name may encompass a complex of closely
related species. All materials listed by Gurjanova (1962)
might therefore be re-examined for this possibility.
Eohaustorius longicarpus, new species
(Fig. 15)
Material examined.
Pusan, South Korea, protected and beach at LW, Jae-Sang
Hong coll., June, 1983. - Female ov (4.0 mm) Holotype
(slide mount); male (4.7 nun). Allotype (slide mount);
female ov. (3. 5 mm ), Paratype. CMN Cat. no. pending.
Diagnosis. Female ov(4.0mm); Head, rostrum. Eyes.
Antenna 1, peduncle 1, anterior margin proximally bare.
Antenna 2, peduncle 4, hind lobe deep, margin with 20-25
plumose setae, postero-distal lobe large; segment 5 medially
deepest; flagellar segment 1 with 1-2 postero-distal setae.
Mandible, palp segment 3 slender, posterior margin
with 10 comb spines. Maxilliped, inner plate broad medi-
ally; outer plate large, broad but short; palp segment 2, inner
lobe broad, large, extending almost to tip of slender seg-
ment 3.
Coxae 1 & 2 small, medium deep. Gnathopods 1 & 2
generally similar to those of E. cheliferus.
Peraeopod 3 ordinary. Peraeopod 4, coxa relatively
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 57
FIG. 15. Eohaustoriuslongicarpus,ney,s^dts. South Korea. Male (4.5 mm); female (4.0 mm).
narrow, deep; basis slender, lacking distal setae; segment 4
with weak anterior oblique spine cluster, hind margin with 3
long plumose setae; segment 5 with anterior oblique row of
slender spines, hind lobe elongate, proximal margin with 3
spine clusters, distal free margin bare; segment 6 slender,
nearly exceeded by hind lobe of segment 5, anterior margin
with 1, posterior margin with 2-3, groups of slender spines
and setae.
Peraeopod 5, hind lobe of coxa narrow, deep, hind
margin strongly setose; basis relatively slender, subovate.
lacking distinct postero-distal lobe; segment 4 short, uni-
formly broad, facial spine rows strong; segment 5 broader
than long, facial spines strong; segment 6 broad, anterior
margin with 3-4 singly inserted or groups of spines, hind
margin distally with 2 slender spines. Peraeopod 6, basis
little expanded distally broadest, with weak distal lobe, hind
margin distally bare of setae; segment large, long, broad
throughout, with 5-6 clusters of facial spines; segment 5
short, very broad distally, with 1 or 2 facial spines, and 5-7
distal margin spines, distal excavation very shallow; seg-
AMPHIPACMCA VOL. 11 NO. 1, AUG. 31, 1995 58
ment 6 straight, hind margin with 6-7 spines, long spines
simple. Peraeopod 7, basis medium broad, hind margin
nearly straight, nearly bare, lacking proximal cusp; segment
4 triangular, broadest distally, hind margin setose; segment
5 subquadrate, anterior margin with 2 spine groups, distal
free margin with 1-2 small spine groups; segment 6 medium,
broadest medially, anterior margin with 1, posterior margin
with 3, clusters of slender spines.
Pleopods, peduncle large, broad; outer ramus with 15?
segments, inner with 10 segments? Pleon plate 3, hind
comer strongly produced, sharply upturned near apex, base
of inner margin with 3 long setae. Uropod 1, rami subequal;
peduncle, outer margin nearly bare, with 2-3 weak distal
spines; inner ramus, posterior margin with 2 setae; outer
ramus with a few posterior marginal spines. Uropod 3, rami
relative short, thick, terminal segment long; inner ramus,
inner margin with 4 long setae. Telson lobes short, thick,
with 5-6 dorso-distal and a few inner marginal setae.
Coxal gills short, saclike
Etymology. From longi - + -karpos (wrist), alluding to
the elongate posterior lobe of the carpus of peraeopod 4.
Distribution. Known only subtidally from sand beaches
in South Korea.
Taxonomic and biogeographical commentary. The
species exhibits mainly pleisiomorphic character states, and
clusters generally with the primitive E. eous complex (F.g.
16, p. 59). It is not closely related to any other species (well
below 75% similarity levels) and the mjterial is regrettably
insufficient for biographic commentary.
Discussion and Conclusions
In this study, the genus Eohaustorius was found to en-
compasses 1 3 described species that are endemic to intertidal
and shallow subtidal waters of the North Pacific marine
region. Their sediment-burrowing and filter-feeding life
styles are accompanied by limb adaptations that are grossly
similar to, but much more highly specialized than, those of
members of the North-Pacific endemic talitroidean family
Dogielinotidae from which they are now phyletically
separated (Bousfield & Tzvetkova, 1982; Barnard &
Karaman, 1991). However, members of the Dogielinotidae
are more advanced phyletically in having strongly sexually
dimorphic gnathopods, and utilizing pre-amplexing
reproductive behaviour (Bousfield & Shih, 1994).
As noted previously (e.g. Barnard, 1957; Bousfield
1 965), Eohaustorius is grossly similar in body form and limb
structure to the 7 other genera of family Haustoriidae most
of whose member species are endemic to the North American
Atlantic region (Bousfield, 1970). However, the species of
Eohaustorius are distinguished not only by their generally
smaller size, but by their less highly specialized mouthparts,
smaller coxae of gnathopods 1 &2,unUke formofperaeopods
3 & 4, generally shorter, broader, and less spinose distal
segments of peraeopods 5-7, lack of a distal ventral lappet on
urosome 1, more setose rami of uropod 3, and the widely
separated (basally unfused) lobes of the telson, among other
differences.
Concerning a common ancestry for these 8 genera, Eo-
haustorius appears least different from the genus Pseudo-
haustorius Bousfield, 1965. Similar character states include
those of: (1) antennae 1 & 2 (flagella short, few segmented);
(2) maxilla 1 (weakly setose inner plate, lack of baler lobe);
(3) maxilla 2 (plates relatively unmodified for filter feeding);
(4) maxilliped palp (segment 3 claviform); (5) peraeopod 6
(segment 6 spatulate [vs. linear]); (6) pleon segment 3
(strongly produced dorso-distally, lateral plate acutely
produced); (7) urosome 1 (peduncle and rami setose, weakly
spinose); (8) urosome 2 (nearly occluded dorsally by urosome
segments 1 & 3); (9) uropod 3 (terminal segment of outer
ramus short) and (10) telson (lobes setose [vs, spinose]).
Some of these character states (e.g., 6, 10), as well as the
subrectangular form of segment 5 of peraeopod 6, are typical
also of the genus Acanthohaustorius. Whether these sim-
ilarities signify relatively close phyletic relationships or
accrue mainly to similarities in lifestyle and habitat of com-
ponent species is moot. If phyletic, morphological similarities
would link two genera that appear to have little readily dis-
cernible biogeographical relationship (see p. 59). An
alternative possibility, that the genus Eohaustorius evolved
independently from a pontoporeiid ancestral group, and that
the family Haustoriidae is therefore polyphyletic, receives
little support from this analysis.
Within the genus Eohaustorius, numerical analysis of
20 selected morphological characters and pertinent character
states of 12 of the 13 described species is summarized in a
phenogram of species similarities (Table I; Fig. 12). The
present modification of the UPGMA cluster analysis system
of Sneath & Sokal (1973) has been used in similar studies of
other North Pacific amphipod groups (e.g., Conlan, 1983;
Jarrett & Bousfield, 1994). Here the analysis is slightly
compromised by limited morphological information available
concerning mouthparts of some western North Pacific species.
Despite the unavoidable emphasis on character states that
may reflect burrowing behaviour rather than phyletic relat-
ionships, the overall results are considered significant.
In the phenogram (Fig. 16) three main groups "cluster
out" at better than 60% similarity levels. In the centre is a
relatively primitive eous group of six species, from both Asi-
atic andNorth American coastal regions, having P.-A. indices
mainly of 13-16, but 23 for the somewhat isolated E. sen-
cillus. The core group is flanked on the left by the somewhat
aberrant Asiatic cheliferus group, with P. -A indices of 13-
20, and on the right by the North American washingtonianus
group, with P. A. Indices of 16-22. The cheliferus group is
characterized by strongly produced and/or distally hooklike
hind comer of pleon plate 3 relatively strongly spinose hind
margin of segment 6 of peraeopod 5, slender telson lobes,
low numbers of comb spines on mandibular palp segment 3,
and well-developed hind lobe of segment 5, peraeopod 4.
Members of the washingtonianus group have a proximal
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31. 1995 59
40
38
> 36
H-
j 32
® 30
O)
28
UJ
< 26
So 24
22
FIG. 16. PHENOGRAM OF NORTH PACIFIC SPECIES OF EOHAUSTORIUS*
abcdefghjklm
cc
LU
I-
o
<
cr
<
X
o
Q
UJ
X
<
Q.
20
18
16
14
12
10
8
"r
13
"T"
20
I I
17 13
"T-
14
"T"
13
16
-T"
15
23
"r
16
SPECIES
A subulicofus
B cheliferus
C robustus
D gurjanoyae
E eetuarius
F ecus
G
H
J
K
L
M
"r
16
sawyer/
longicarpus
senci/lus
wastiingtonianua
brevicuspis
barnardi
22 P.-A. INDEX
75
>-
X
<
50
CO
25
* except. E. tandeensis Dang, 1968
cusp on the posterior margin of the basis of peraeopod 7, one
spine cluster on the postero-distal margin of segment 5 of
peraeopod 4, and a relatively large maxilliped palp segment
3. The core eous group shows mainly plesiomorphic char-
acter states, including a relatively elongate, facially and
marginally spinose, segment 4 of peraeopod 6 that typifies
most Atlantic genera of haustoriinids. E. sencillus is
uniquely advanced in its very short antennal flagella, enlarged
dactyl of gnathopod 1, and short maxilliped palp segment 3.
All in all, few species pairings exhibit greater than 75%
similarity and none is closely related, suggesting long peri-
ods of isolation and limited gene flow between populations.
The relatively primitive nature of intertidal vs. subtidal spec-
ies of Eohaustorius is consistent with similar trends in other
regional fossorial amphipods (e.g, Jarrett & Bousfield, 1 994a).
Biogeographical Considerations
The subregional occurrence of species of Eohaustorius
is provided in Table II. Of the twelve species considered
here, five are endemic to Asiatic North Pacific shores, and
six to the North American coast. Only one species, E. eous,
occurs in both continental waters, and only in the Bering Sea
region.
In the Asiatic region, E. robustus and E. cheliferus are
confined mainly to the Sea of Okhotsk and Kamchatka
regions whereas E. gurjanovae, E. longicarpus and £. sub-
ulicolus have been recorded exclusively or mainly from
southern Sakhalin Island and the Sea of Japan. In the more
southerly region, these haustoriid species overlap distri-
butionally, in similar sedimentary habitats, with members of
the talitroidean fossorial family Dogielinotidae. The dogiel-
AMPHIPACIFICA VOL. 11 NO, 1, AUG. 31, 1995 60
TABLE I. CHARACTERS AND CHARACTER STATES OF SPECIES OF EOffAl/SrO/f/l/S
CHARACTER STATE VALUE
CHARACTER
Plesiomorphic
0
Intermediate
1
Apomorphic
2 ■
1. Antenna 2, peduncle 4, number of
<20
25
>30
posterior marginal setae
2. Antenna 2, flagellar segment 1,
1
2
3+
number postero-distal long setae
3. Mandibular palp segment 3, number of
10+
7
5
posterior marginal comb spines
Small
4. Maxilliped palp, segment 3, size
Large
5. Peraeopod 3, coxal shape
Squarish
Semilunate
6. Peraeopod 4, hind lobe of segment 5
Short
W>L
Long
L»W
7. Peraeopod 4, segment 5, hind lobe,
Absent
Present
distal marginal spines
8. Peraeopod 5, length of segment 4
Long
Short
9. Peraeopod 5, shape of segment 5
Narrow
Wide
10. Peraeopod 5, segment 6, number
2-3
1
of posterior marginal spines
11. Peraeopod 6, length of segment 4
Long
L»W
Short
W=L
12. Peraeopod 6, segment 5, number
2
1
of anterior marginal spine clusters
13. Peraeopod 6, segment 4, hind
1+
0
marginal spines
14. Peraeopod 7, basis, proximal hind
lacking
present
marginal cusp
15. Peraeopod 7, segment 5, number
2-3
1
of anterior marginal spine clusters
16. Peraeopod 7 segment 6, number
3-4
2
1
of posterior marginal spine clusters
17. Pleon plate 3, type of hind process
short
medium
straight
long, hooked
18. Uropod 1, inner ramus, number of
5+
2
0
posterior marginal setae
19. Uropod 3, size of terminal seg-
Long
short
ment of outer ramus
20. Telson lobes, form.
elongate
short
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 61
TABLE II.. DISTRIBUTION OF NORTH PACIFIC SPECIES OF EOHAUSTORIUS
SPECIES
BIOGEOGRAPH
I CAL ZONES
1
2
3
4
5
6
7
8
9
E. subulicolus'^
X
E, longicarpus^
X
E, gurjanovae^
X
X
E, cheliferus^
X
X
E, robustus^
X
E. eous^
X
X
E, estuarius*
9
X
X
X
9
E. washingtonianus*
X
X
X
X
X
E. brevicuspis*
X
X
X
E. sawyeri*
X
X
X
X
E. sencillus^
X
X
X
E. barnardi^
X
X
ZONES: 1. Japan Sea and southward 2. Sea of Okhotsk region 3. Bering Sea -W.Alaska
4. Southeastern Alaska 5. Northern British Columbia 6. Southern British Columbia
7. Washington-Oregon 8. North & Central California 9. Southern & Baja California
Ecology:* Intertidal; ^ Subtidal
inotid species, of similar or slightly larger size, tend to occur
mainly intertidally, during summer months at least, along
sandy beaches and in estuaries, often in very high densities
(Kamihira, 198 1 ; Bousfield & Tzvetkova, 1982). The north-
ernmost beaches are subject to freezing and ice scour, esp-
ecially during the winter and early spring, during which time
the dogielinotids shift from the littoral to the infralittoral
zone. The regional haustoriid species occur subtidally, at
least during summer months, and probably year-round.
Perhaps intense competition with the filter-feeding and “sand-
licking” dogielinotids in summer, and rigorous physical con-
ditions in winter, are factors that have apparently prevented
evolution of Asiatic regional intertidal haustoriid species.
Along North American Pacific sandy shores however,
the situation is strongly contrasting. Of the six species
recorded from southeastern Alaska to southern California,
the four northernmost species, E. estuarius, E.
washingtonianus, E. brevicuspis and E. sawyeri occur
essentially intertidally and shallow sublittorally. As noted
on page 59, and in figure 16, these northern species show
mostly plesiomorphic character states and probably evolved
early during the penetration of the genus into the North
Pacific region. The two southermost species, E. sencillus
and E. bamardi, are strictly subtidal and their character
states are significantly more advanced. However, the
northern intertidal species and one southern subtidal species
(£. sencillus) all co-occur in biogeographical zone 6
(Washington-Oregon), the very region in which the single
North American dogielinotid species, Probosdnotus loquax
(Barnard, 1967) occurs intertidally in great abundance
(Hughes, 1982). '^\^%ptc\^^,dS[d.Eohaustonusbrevicuspis,
co-occur intertidally on open surf sand beaches and are
AMPHIPACIFICA VOL. 11 NO. 1, AUG. 31, 1995 62
presumed to be heavily preyed upon by shore birds, especially
during late summer. However, despite these negative
factors of competition and predation, intertidal haustoriids
are able to occur commonly throughout zone 6, and indeed
zones 4-9, almost certainly because of year-round near
uniformity of coastal marine conditions; water temperature
seldom fall below 5®C, and winter ice scour is non-existent
(Thomson, 1981). These near-uniform physical conditions
probably account for the relatively wide geographical range
of the North American species, each of which occurs in 3-5
biogeographical zones vs. the 1-2 zones of the Asiatic
species.
With respect to its overall biogeographical affinities,
Eohaustorius is essentially a cold temperate genus and, in
this respect, closer to the presumed para-ancestral ponto-
poreiid and perhaps distantly ancestral gammaroidean groups
that are restricted to holarctic regions (Bousfield, 1970;
Bousfield & Shih, 1994). In the North Pacific, members of
the genus Eohaustorius occur well north of 60^^ north lati-
tude, and into the Bering Sea region, but apparently not into
arctic waters where the Pontoporeiidae dominate (Bousfield,
1987). In the western North Atlantic region, however, the 7
haustoriid genera are essentially temperate, and warm- temp-
erate in thermal requirements. Species of the most eurytopic
genus, Haustorius, range along North American shores
north only to latitude 47® (southern Gulf of St. Lawrence)
where they appear to be limited intertidally by the severity
and duration of winter conditions (Bousfield, 1965). In
western Europe, however, where winter conditions are
relatively mild and reminiscent of those of the western north
Pacific, the species H. arenarius attains 60® north latitude
(southern Norway) (Lincoln, 1979).
In conclusion, we have noted on p. 59 that Eohaustorius
is grossly similar morphologically to the North Atlantic
complex of haustoriid genera, but is here found biogeo-
graphically unrelated to them. In absence of firm evidence
to the contrary, the genus Eohaustorius is here surmised to
have been isolated in the North Pacific for a considerable
period of time. An hypothetical subtidal common ancestor
may have connected it directly to the relatively primitive
North Atlantic genus, Pseudohaustorius, possibly during the
early Miocene epoch. At that time, the Panama isthmus had
not yet formed and suitably cool marine connections existed
between Atlantic and Pacific coastal marine regions (Adams,
1981). Although such an explanation is not entirely
satisfactory, it does accord reasonably with rationale proposed
for similar Pacific-Atlantic disjunct distributions in other
amphipod groups. Thus, in some members of the fossorial
phoxocephalid genus Eobrolgus (Jarrett and Bousfield,
1994b) and in two species of the non-substrate modifiying
parapleustin genus Incisocalliope (Bousfield and Hendrycks,
1995), the distributional hiatus and its explanation may be
similar, but the evidence for it appears to be more compelling.
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golfiellidean Amphipoda recorded from the vicinity of
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new subfamily. Amphipacifica I (1): 58-140.
, & E. L. Bousfield, 1994b. The amphipod sup-
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America. Family Phoxocephahdae. Part II. Subfamilies
Pontharpiniinae, Parharpiniinae, Brolginae, Phoxoceph-
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Lincoln, R. J., 1979. British Marine Amphipoda. London:
British Museum (Natural History). 658 pp., 280 figs.
McLeay, et al. 1992. Acute Test for Sediment Toxicity Us-
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Sneath, P. H. A., & R. R. Sokal, 1973. Numerical Taxon-
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Staude, C. P., 1987. Amphipoda: Suborder Gammaridea.
pp. 346-391. ip E. Kozloff (ed.) Intertidal Invertebrates
of the Pacifc Northwest. University Washington Press,
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Stebbing, T. R. R., 1906. Amphipoda: Gamaridea. Das
Tierreich. I. Berlin. 806 pp.
Thomson, R. E., 1981. Oceanography of the British Col-
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AMPHIPACMCA VOL. 11 NO. 1, AUG. 31, 1995 64
The Canadian Field-Naturalist
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Francis R. Cook
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
65
THE AMPHIPOD FAMILY PLEUSTIDAE ON THE PACIFIC COAST OF NORTH AMERICA: PART IH.
SUBFAMILIES PARAPLEUSTINAE, DACTYLOPLEUSTINAE, AND PLEUSIRINAE. SYSTEMATICS AND
DISTRIBUTIONAL ECOLOGY.
by E, L. Bouslield^ & E. A. Hendrycks^
ABSTRACT
The gammaridean amphipod subfamily Parapleustinae Bousfield & Hendrycks, 1994, contains 28 described species
of which 26 have been recorded from coastal marine regions of the North Pacific Ocean. From shallow coastal shelf waters
of the both continental coasts are here described and figured the following tax a: Parapleustes americanus, new species;
P . ishimarui, new species; Chromopleustes lineatus, new genus, new species; Gnathopleustes serratus new genus,
new species, G. simplex, new species; G. trichodus, new species; G. pachychaetus, new species; Trachypleustes
vancouverensis, new genus, new species; T. trevori, new species; Micropleustesnautiloides, new genus, new species
and M, behningiodes, new species. Also proposed for inclusion within the subfamily ar^ Commensipleustes, new genus
(type species; C. commensalis (Shoemaker, 1952); Incisocalliope J. L. Barnard, 1959 (revived status) (type species;
/. newportensis Barnard, 1959). This genus contains eight species of which is newly described
from the Sea of Japan. Also variously redescribed, or treated, are; Gnathopleustes den (J. L. Barnard, 1969b); G.
pugettensis (Dana, \%5^)\ Incisocalliope newportensis J. L. Barnard, 1959; /. bairdi (Boeck, 1871); Chromopleustes
oculatus (Holmes, 1908); C. johanseni (Guijanova, 1951); Micropleustes nautilus (J. L. Barnard, 1969b) and M.
behningi (Guijanova, 1938). Dactylopleustes echinoides, new species (subfamily Dactylopleustinae Bousfield &
Hendrycks, 1994) is newly described and figured, andPleusirus secorrus J. L. Barnard, 1969b (subfamily Pleusirinae
Bousfield & Hendrycks, 1994) is redescribed and figured.
Taxonomically, the seven parapleustin genera were found to be morphologically distinctive, and not very closely
similar. A modified phenetic cluster analysis indicated that the most southerly, temperate and subtropical genus
Incisocalliope is phyletically most advanced, and that the mainly N. American cold temperate genus Chromopleustes
is the most primitive, despite the relatively advanced nature of its mouthparts, and weakly sexually dimorphic gnathopods.
Biogeographically, of the 26 species of Parapleustinae recorded from the North Pacific region, 16 species (in seven
genera; occur along the North American coast, nine species (in four genera) along Asiatic shores, and one species in
the Hawaiian Islands, south central North Pacific. The genera Parapleustes, Chromopleustes, Micropleustes,
Dactylopleustes andPleusirus are Pan-Pacific, with approximately equal numbers of species on North American and
Asiatic coasts. However, the generaTrachypleustes, Gnathopleustes and Commensipleustes, containing about a dozen
species in total, are apparently endemic to the North American Pacific region. The isolated occurrence of Parapleustes
gracilis (Buchholz, 1874), and Incisocalliope aestuarius (Watling & Maurer, 1973) in different temperature regimes of
the North Atlantic region, appear anomalous. Although explanations proposed for such disjunct distributions are not
entirely satisfactory, they underscore the high regional endemicity of subfamily Parpleustinae within the North Pacific
Basin.
INTRODUCTION
Pleustid amphipods form an important assemblage of
microcarnivorous amphipod crustaceans in the North Pacific
marine region. Of the 12 recognized subfamilies (Bousfield
& Hendrycks, 1994), the Parapleustinae, with nearly 30
described species, is one of the largest and numerically
dominant groups in shallow-water habitats of both Asiatic
and North America coasts. The monotypic subfamily
Pleusirinae is common along the North American coast.
Species of Dactylopleustinae are commensals on echinoid
echinoderms, rarely encountered, and the subfamily prob-
ably more diverse than the three known species would
indicate.
Prior to the present investigation, only eight species of
subfamily Parapleustinae had been recorded from North
Amer-ican Pacific localites, all of which had been relegated
to the genus Parapleustes by Barnard & Karman (1991).
1 Research Associate, Royal Ontario Museum, Toronto, Canada :
2 Research Assistant, Canadian Museum of Nature, Ottawa, Canac
Early 19th century records of Dana, Stimpson, Boeck and
others had been capably summarized by Stebbing (1906). In
the first half of this century. Holmes (1908) described Ple-
ustes oculatus from off California. Few other records accrued
until J. L. Barnard commenced his monumental series of
studies (1952, 1954, 1956 et sequ.) on amphipod commun-
ities of the California coast. His paper with Given (1960)
summarized information on five parapleustins known to that
date, including Parapleustes newportensis Barnard, 1959,
that had been described initially as the type species of a new
genus, Incisocalliope. Shoemaker (1952) had earlier des-
cribed P. commensalis from the pleopods of a spiny lobster
off southern California, and later (1964, posthumously)
added to records of Dana's "Parapleustes pugettensis" from
Dillon Beach, California. Dana's species name was here
found to embody several distinct taxa, mostly new to science.
Barnard (1969b) described Parapleustes den, P. nautilus
and Pleusirus secorrus from the Central California coast,
KIP 6P4.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
66
and the following year (1970) added P. derzhavini makiki
from the Hawaiian Islands. Very recently, Barnard &
Karaman (1991) submerged P.johanseni Gurjanova, within
P. oculatus Holmes, and synonymizedP. bairdi (Boeck) and
P. newportensis (Barnard) with P. pugettensis (Dana). The
pragmatic illustrated keys of Barnard ( 1975), Staude (1987),
and the regional annotated listing of Austin (1985), provide
useful summaries of existing knowledge and bases on which
to conduct further studies.
On the Asiatic Pacific coast, work on parapleustins
commenced with Gurjanova’s description of Neopleustes
derzhavini and Pleustes behningi (1938) and Parapleustes
johanseni (1951). Kudryaschov (1972) provided records of
P. nautilus (later proven to be a new species). Tzvetkova
(1975) described the echinoid commensal species Para-
pleustes echinoicus, later given separate generic status (as
Dactylopleustes) by Karaman & Barnard (1979). Kudry-
aschov & Tzvetkova (1975) concluded the Russian contrib-
ution with a description of Pleusirus secorrus asiaticus.
Workers from Japan entered the western Pacific para-
pleustin scene with Irie & Nagata's preliminary regional
listing (1962) of "Parapleustes oculatus" and "P. pugettensis".
Ishimaru (1984) contributed most significantly with Para-
pleustes dilatatus n. sp., P. longimanus, n. sp., and records
of Parapleustes gracilis Buchholz, P. behningi Gurjanova,
and P. derzhavini Gurjanova. Soon after, Ishimaru (1985)
added Pleusirus secorrus to the regional list. Hirayama
(1988) described Parapleustes filialis, n. sp. and Dactylo-
pleustes obsolescens, n. sp. Finally, Ishimaru (1994) treated
the entire pleustid fauna of Japan in his useful regional
catalogue of gammaridean and ingolfiellidean species.
The previous studies had revealed a significant new
fauna of parapleustinids, pleusirins and dactylopleustins in
the western Pacific and Californian regions. However,
corresponding faunas of the enormous intervening costal
areas were virtually unknown. Based on extensive new
material from the coasts of British Columbia, southeastern
Alaska, and Washington and Oregon states, the present study
attempts to fill this large hiatus in systematic knowledge. It
also attempts to relate these faunas phyletically and bio-
geographically to faunas of adjacent regions and elsewhere.
ACKNOWLEDGEMENTS
The authors are greatly indebted to colleagues and their
research institutions who provided field assistance, facilities
and materials that made this study possible. Most of the field
work was conducted by the senior author (ELB) during the
period 1955 -1980, station lists for which have previously
been made available (Bousfield 1958, 1963, 1968;Bousfield
&Jarrett, 1981; Bousfield & McAllister, 1962). Ship-assisted
parts of the work were based at the Pacific Biological Station,
Nanaimo, with the help of the late D. B . (Dan) Quayle; at the
Pacific Environmental Institute, West Vancouver, with the
help of C. D. Levings; at the Bamfield Marine Station, with
the help of A. D. Spencer and colleagues, and at the Friday
Harbor Laboratories, with the help of C. P. Staude.
The bulk of the study material is currently maintained by
the Invertebrate Collections Unit, Canadian Museum of
Nature (CMN), Ottawa. For the loan of study specimens, the
authors thank Dr P. Slattery, Moss Landing, CA (Bering Sea
material); the Los Angeles County Museum, Los Angeles,
CA (J. L. Barnard material from Southern California), Dr
Akira Hirayama, Kumamoto, Japan (Japanese material and
from Russia (formerly USSR), Nina Tzvetkova, and the late
Eupraxie F. Gurjanova whose extensive publications on the
far-eastern pleustid fauna have been invaluable reference
bases for the present study. Helpful commentary on various
phases of manuscript preparation was provided by Pierre
Brunei, University of Montreal, Roger Lincoln, British Mus-
eum, C. P. Staude, Friday Harbor Laboratories, K. E. Con-
lan, CMN, Ottawa, and Patrick Shaw, Vancouver, B. C.
The line illustrations were prepared with the most capable
assistance of Susan Laurie-Bourque, Hull, Quebec (see
legend for figures, p. 133). Maijorie Bousfield, Montreal,
provided translations of pertinent Russian literature.
SYSTEMATICS
Family PLEUSTID AE
PARAPLEUSTINAE, Bousfield & Hendrycks, emended
Parapleustinae Bousfield & Hendrycks, 1994; 41.
Type genus. Parapleustes Buchholz, 1874 (p. 67).
Genera. Chromopleustes, new genus (p. 73); Com-
mensipleustes, new genus (p. 82); Gnathopleustes, new
genus (p. 82); Incisocalliope J. L. Barnard (p. 95); Trachy-
pleustes, new genus (p. 105); Micropleustes, nev^ genus (p.
111 );.
Removals. Parapleustes assimilis (Sars,1883); P.
bicuspis (Kroyer, 1838); P. monocuspis Sars, 1895; P. gag-
arae Gurjanova, 1972; P. major Bulycheva, 1952, P. bi-
cuspoides NugatSi, 1965; P. sinuipalmaDunbar, 1947, P. tri-
anguloculatusBulycheva, 1952; P. tricuspislshimaru, 1984,
to genera within subfamily Neopleustinae (Bousfield &
Hendrycks, 1994, and in prep.).
Diagnosis. Body generally small to medium, smooth
above, not mucronate on pleon; external surface pattern
often colourful or disruptive. Head, rostrum short, little or
not exceeding rounded lateral head lobe. Eyes variable in
size and form, usually medium large, subrotund. Antennae
usually elongate; antenna 1 the longer, occasionally short,
peduncular segments often shortened. Accessory flagellum
minute.
Mouthparts generally strongly modified. Upper lip
distinctly notched, lobes variously asymmetrical. Lower lip
broad, squat, outer lobes oblique. Mandible, molar small,
weak, thumblike, apex pilose, triturating surface lacking or
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
67
vestigial; blades generally numerous, often strongly modified:
chisel-shaped, cusplike, or molarized in form; left lacinia
wide, multidentate, cutting edge straight; right lacinia lack-
ing; incisor multidentate, third (distal) tooth largest; palp
segment 3 not shorter than 2, with basal “A” seta (of Cole,
1980). Maxilla 1, inner plate with single apical seta; outer
plate with 9 (rarely 15-18) apical spine teeth; palp occasionally
broadened, with distal facial setae, apices spinose; segment
1 often with lateral ("shoulder") seta(e). Maxilla 2 ordinary,
inner palate with stout inner marginal plumose seta(e).
Maxilliped; palp strong, segment 2 usually longest, 3 lacking
distinct distal process; outer plate narrow (vertical margins
subparallel), sparsely setose and/or spinose; inner plate
short, apex with “button” spines, inner margin with few setae
and/or spines.
Coxal plates large, deep, broad; coxa 1 generally broad-
ening distally and rounded below; hind comers cuspate.
Gnathopods various; weak to medium strongly developed;
gnathopod 2 slightly larger, differing slightly in form, and
occasionally sexually dimorphic. Gnathopod 1, basis, margins
variously setose; meral cusp weak; propod, palm usually
oblique, convex, with median tooth.
Peraeopods 3 & 4 ordinary, normally spinose, dactyls
short to medium. Peraeopods 5-7 homopodous; coxae
medium deep, hind margins rounded, laterally smooth;
segment 4 longer than 5 which it variously overhangs behind.
Pleon plates 2-3, hind comers acuminate, not produced.
Pleopods medium strong, ordinary. Uropods 1 & 2 ordinary;
peduncle of uropod 1 with prominent distolateral spine; rami
elongate, outer shorter, margins and apex strongly spin-ose.
Uropod 3, inner ramus markedly the longer, margins spinose.
Telson elongate, narrowing distally, keeled proximally;
apex rounded; penicillate setae medio-distal.
Coxal gills variable, smaller and saclike anteriorly,
larger, platelike posteriorly. Brood plates large, broad.
Distributional ecology. The subfamily is essentially
endemic to eulittoral shelf habitats of the North Pacific
region. However, three species occur in isolation elsewhere,
viz., the northeastern North Atlantic, the western North
Atlantic, and the Hawaiian Islands of the central North
Pacific (seep. 131).
Taxonomic commentary. The Parapleustinae is closely
allied to subfamily Neopleustinae (Bousfield & Hendrycks,
1994). The latter differs, however, in having a well-developed
keeled rostmm, dorsal body processes, a short, nearly centrally
keeled telson, large mandibular palp, and a distally oblique
and processiferous maxillipedal palp segment 3. Also,
component members of the Neopleustinae occur in deep cold
waters of the Arctic, North Atlantic and North Pacific
regions; none is intertidal.
Numerical taxonomic analysis of the Parapleustinae
reveals a complex of 7 generic-level subgroups (Fig. 43, p.
127), the species of which are treated systematically below.
Parapleustes Buchholz
Parapleustes Buchholz, 1874: 337.— Stebbing 1906: 320.—
Gurjanova, 1951: 648 (partim).— Barnard 1969a: 425
(partim). — Barnard & Karaman, 1991: 649 (part).
Type species, Parapleustes gracilis Buchholz, 1874.
Species composition (North Pacific). Parapleustes
ishimarui (= P. gracilis Ishimaru, 1984) (p. 70); and P.
americanus, new species (p. 71).
Diagnosis. Body small, smooth above. Head, rostrum
very short; anterior head lobe subacute; inferior antennal
sinus broadly incised. Eye medium, elliptical to roundish.
Antennae slender, medium long, weakly setose. Antenna 1
typically the longer; peduncle 3 short; peduncle 1, distal
process weak; accessory flagellum minute.
Mouthparts modified. Upper lip shallowly notched,
lobes asymmetrical. Lower lip medium wide, squat; outer
lobes thick, rounded, oblique. Mandible: molar reduced to
a blunt setulose knob; incisor irregularly toothed, distal teeth
smaller; left lacinia 8-10 dentate; blades 5-12 in row, stout,
weakly molarized; palp slender, segment 3 with few (3-5),
posterior marginal “D” spines; maxilla 1, outer plate with 9
mainly tall apical spines; palp not broadened, with -4 apical
spines and several oblique subapical (facial) setae. Maxilla
2, inner plate little broadened, with marginal plumose seta.
Maxilliped, palp strong, dactyl strong, segment 3 lacking
distal process; segment 2 largest; outer plate short, little or
not longer than inner, 1(2) apical spines; inner plate with few
apical button spines and few marginal setae.
Coxal plates wide, deeper than respective body plates;
lower margins straight, hind notch(es) distinct; coxa 1 little
smaller than 2, slightly expanded distally.
Gnathopods medium large, closely subequal, little or
not sexually dimorphic; propods broadening distally, palms
smoothly convex, usually with central median tooth, postero-
distal angle with 1-2 clusters of spines not extending onto
palm; hind margin smooth, about equal in length to palm;
carpus usually short, hind lobe deep; postero-distal process
of merus acutely produced; bases slender, antero-marginal
setae distally restricted.
Peraeopods 3-7 slender, weakly spinose; segment 5 and
dactyls slender, relatively long. Peraeopods 3-4, margins of
segments 4-6 weakly spinose, lacking special setae.
Peraeopods 5-7 regularly homopodous, bases broad, convex
behind.
Pleon plates broad, deep, smooth behind, hind comers
weakly acuminate. Pleopods strong, not sexually dimorphic.
Urosome short; urosome 2 not occluded dorsally. Uropods
1 & 2 rami slender, tips spinose, usually extending beyond
uropod 3. Uropod 1, peduncle with distinct latero-distal
spine; rarm subequal in length. Uropod 2, inner ramus the
longer. Uropod 3, inner ramus markedly the longer.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
68
KEY TO KNOWN GENERA OF SUBFAMILY PARAPLEUSTINAE
1. Gnathopods 1 & 2, palm of propod with median tooth present, variously developed; gnathopod propod,
length of palm about equal to (or longer than) posterior margin; gnathopod propods, hind margin lack-
ing setae (except some Incisocalliope)’, gnathopod 2, carpus always relatively short, anterior margin
<1/2 length of propod 3.
— Gnathopods 1 & 2, propodal palm, median tooth lacking or very reduced; gnathopod propod, length of
palm short, usually much less than posterior margin (except in some Micropleustes)\ propod, hind mar-
gin with 1 - 4 setae or setal groups; gnathopod 2, carpus usually elongate, anterior margin about equal
in length to propod (except some Micropleustes) 2.
2. Antennae slender, flagella elongate, antenna 1 usually markedly the longer; peraeopods 5-7, segment 4
postero-distally overhanging segment 5 by less than 1/4 length of segment 5; coxal plates 2 - 4 not ex-
ceptionally large and/or deep, distal portions of respective bases exposed below, hind cusps of coxae
2 & 3 single Chromopleustes (p. 73)
— Antennae short, stout, subequal, flagella little (or not) longer than respective peduncles; peraeopods 5 -
7, segment 4 overhanging segment 5 postero-distally by nearly half length of segment 5; coxae 2 - 4
large and deep, totally masking respective bases, hind comers with 2-5 small cusps (rarely single) ....
Micropleustes (p. Ill)
3. Antennae short, flagellum; of A1 little longer than peduncle, of A2 shorter than peduncle; gnathopods 1
& 2, carpus very short, length less than 1/4 that of propod, hind lobe small, narrow; pleon plate 3, hind
comer with small hook Parapleustes (p. 67)
— Antennae normally elongate, flagellum distinctly longer than respective peduncle; gnathopds, dorsal
margin of carpus more than one-fourth length of propod, hind lobe about half as wide as its dorsal mar-
gin; pleon plate 3, hind comer acuminate, not mucronate 4.
4. Peraeopods 5-7, segment 6 broadened distally, anterior margin with stout spines, forming (with dactyl)
a grasping organ; maxilliped, outer plate shorter than inner plate; coxa 1 not noticeably broadening
distally, hind margin lacking proximal short spine(s) Commensipleustes (p. 82)
— Peraeopods 5-7, segment 6 normally slender and spinose; maxilliped, outer plate slightly longer than
inner plate; coxa 1 broadening distally, hind margin with proximal spine(s) 5.
5. Gnathopods large, strongly subchelate, variously sexually dimorphic; basis, anterior marginal setae
confined to distal angle; antenna 2, peduncular segments not shortened, surfaces armed variously with
clusters of short setae Gnathopleustes (p. 82)
— Gnathopods medium subchelate, propod and carpus combined shorter than depth of coxa, not sexually
dimorphic; basis, anterior margin often setose throughout; antenna 2, peduncular segments 4 & 5
shortened and/or bare of surface setal groups 6.
6. Antenna 1, peduncular segment 2 short, less than half length of segment 1; mandible, palp segment 2
weakly setose (6-7 setae); left lacinia 10-12 dentate; maxilliped, palp segment 3 lined medio-distally
with short spines Incisocalliope (p. 95)
— Antenna 1, peduncular segment 2 not shortened, length greater than half that of segment 1; mandible,
palp segment 2 with numerous (10-15) medial setae; left lacinia 7-9 dentate; maxilliped, palp segment
3 lacking distal short spines Trachypleustes (p. 105)
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
69
FIG. 1. Parapleustes gracilis Buchholz. Female (2.5 mm). Norwegian Sea. (after Sars, 1895).
Telson medium long, narrowing, subacute; dorsal
penicillate setae slightly distad (of middle). Coxal gills sac-
like, medium, unequal, smallest anteriorly.
Taxonomic commentary. The following species are
TQmoytdfromParapleustes, sens. str.\ P. assimilis Sars and
P. tricarinatus lsYmR^nx-{\.oNeopleustesy,andP. commens-
alis Shoemaker (to Commensipleustes), for the following
combination of reasons: lack of a disto-lateral spine on the
peduncle of uropod 1 ; the peraeopods are too long, or stout,
dactyls too short; gnathopod propods are too slender, and/or
the posterior margin is too strongly setose; the palmar tooth
is lacking; the carpus is too long, shallow; the mouthparts are
significantly different, especially in the mandibular blades;
and the pleon is dorsally carinate.
Within Parapleustes proper, the markedly smooth
propods and narrow carpal lobes of the gnathopods might
suggest a closer relationship with the genera Pleustes and
Pleusymtes.
Distributional commentary. The genus Parapleustes
(sens, str.) is essentially arctic-subarctic in present distribut-
ion, dipping southward variably, and mainly subtidally in the
North Pacific and northern North Atlantic regions. Para-
pleustes gracilis is not typical of the subfamily but became
the type species because it is the only member occurring in
the North Atlantic region where amphipod taxonomy began.
Parapleustes gracilis Buchholz
(Fig. 1)
Parapleustes gracilis Buchholz, 1874; 337, fig. 1.— Steb-
bing, 1906: 320.— Gurjanova, 1951: 648, fig. 444.— Bar-
nard & Karaman, 1991: 650.
non Parapleustes gracilis Ishimaru, 1984. — Hirayama,
1988?
Paramphithoe brevicomis G. O. Sars, 1895: 353, pi 124. 2.
Diagnosis. Female (2.5 mm); Head, eye medium
roundish, black. Antenna 1, peduncular segment 2 short,
length -1/2 segment 1; flagellum 13-segmented. Antenna
2, peduncular segments 4 & 5 slender, subequal; flagellum
8-segmented.
Mouthparts not described (notin Sars 1895, norStebbing,
1906) but probably similar to those ofP. americanus (p.71).
Coxae 1-3 deep, medium broad, lower margins weakly
convex, hind comers each with single cusp. Gnathopod 1,
basis with weak antero-distal setal cluster; mems with acute
postero-distal process; carpus short, hind lobe narrow, deep;
propod distinctly expanding distally, inner face smooth;
palmar margin oblique, convex, postero-distal angle with
spine groups on either side of distinct dactyl-tip depression.
Gnathopod 2 closely similar in size and form; basis, antero-
distal margin with several setae.
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
70
Peraeopods 3 & 4, bases with several antero-distal
setae; segments 4-6 slender, elongate (especially segment
6); segments 4 & 5 subequal in length; marginal setae sparse;
dactyl curved, elongate, length >1/2 segment 6. Peraeopods
5-7 slender, bases medium broad, postero-distal lobes shallow;
segments 4 & 5 subequal; segmentb elongate; dactyl elongate,
length > 1/2 segment 6.
Pleon plate 3 , hind comer weakly acuminate, not hooked .
Urosome 2 with free dorsal margin. Uropods 1-2 slender,
peduncle and rami weakly spinose. Uropod 3, outer ramus
2/3 length of slender inner ramus . Telson medium, length
~1.5X basal width, apex subacute.
fauna. Of the 21 species of Parapleustes listed by Barnard
& Karaman, most are members of subfamily Parapleustinae,
but only P. gracilis (= P. brevicomis Buchholz?) is retained
in the genus Parapleustes. All others are removed to other
genera, and in some cases, other subfamilies. It has been
found advisable to restore to the original position a number
of transfers, and a number of synonymies, by others. Thus,
Micropleustes nautilus is removed from the synonomy of M.
behningi, and restored to full species recognition, and the
genus Incisocalliope J. L. Barnard, 1959, is removed from
the synonomy of Parapleustes Buchholz and restored to its
original full generic position.
Distributional commentary. This species is endemic
to arctic and arctic-boreal, North Atlantic waters. It has not
been recorded authentically from the North Pacific region.
As the type species of the genus, this North Atlantic form is
included here for comparative purposes with North Pacific
material previously ascribed to the name Parapleustes gracilis
(above).
Taxonomic commentary. Parapleustes gracilis is the
type of a small group of species here restricted to a few
members of the North Atlantic and North Pacific pleustid
Parapleustes ishimarui, new species
(Fig. 2)
Parapleustes gracilis Ishimaru, 1984; 432, figs. 21-24. —
Ishimaru, 1994: 54.
Diagnosis. Female (2.4 mm): Head, eyes small, round,
black. Antennae short. Antenna 1, peduncular segment 2
medium, length > 2/3 peduncular segment; accessory
flagellum, apex rounded, with 1 plumose and 2 simple setae;
flagellum 9-10 segmented. Antenna 2, peduncular segment
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
71
KEY TO KNOWN SPECIES OF PARAPLEUSTES (SENS. STR.)
. 1 , peduncle 2 short; peraeopod 7, basis, posterior margin nearly straight; uropods 1 & 2, rami shorter
-A~T ^ f P- (Buchholz)(p. 69)
enna 1, peduncle 2 normal; peraeopod 7, basts, posterior margin strongly convex; uropods 1 & 2
inner ramus about equal m length to peduncle; peraeopods 1 & 2, dactyls shorter (<l/2 propod) . . , . ’ 2.
2 Peraeopod 7, basis finely crenulate; pleon plate 3, hind comer forming small hook or mucrona; eye
large, ovme; naaxtlhped outer plate short antericanus. n. sp. (p. 73)
Peraeopod 7, basts with few (8) large posterior notches along posterior margin; pleon plate 3, hind
comer blunt-acuminate; eye small, round; maxilliped, outer plate normal, equal in length to inner plate .
P. ishimarui, n. sp (p. 71)
5 slender, slightly shorter than segment 4; flagellum short, 6-
segmented.
Upper lip conical, apex shallowly incised, lobes slightly
asymmetrical. Lower lip, inner lobes deep, not broad; outer
lobes shallowly oblique. Mandible, molarprominent. slightly
upturned apically; spine row with 6-7 short blades; cutting
edge (left) with 3-4 large teeth proximally and 4 small
denticles distally; palp segment 3, basal “A” setae short;
postero-distal margin with 4 pectinate “D” spines; left lacinia
10-dentate. Maxilla 1, inner plate with single short seta;
palp, apex sharply rounded, with 4 slender spines. Maxilla
2, inner plate broad, length nearly equal to outer plate, inner
margin with short proximal seta. Maxilliped, inner plate
broad, with 3 apical marginal “button” spines; outer plate
medium, taller than inner plate, apex blunt, with 2 unequal
slender spines; palp segment 3 slender, dactyl slender almost
straight.
Coxae 1-3 lower margins get^y convex, hind comers
with single cusp. Coxa 4 hind marginal process rounded.
Gnathopod 1, basis with weak antero-distal setae; merus
with cusp; carpus short, hind lobe narrow, deep; propod
expanding distally with weak inferior facial setae, palmar
margin longer than convex posterior margin, postero-distal
angle with weak distal and strong proximal spine groups
adjacent to dactyl-tip depression. Gnathopod 2 closely
similar in form but propod slightly smaller, and basis lacking
antero-distal setal group.
Peraeopods 3 & 4 regular, slender, segment 5 relatively
short (<segment 4), margins weakly spinose; dactyl short (~
1/3 segment 6). Peraeopods 5-7 subsimilar, increasing
slightly in size posteriorly; segment 4 and dactyl relatively
short. Peraeopod 7, basis more broadly expanded, hind
margin weakly crenulate.
Pleon plate 3, hind comer subquadrate. Uropods 1 & 2
relatively short, margins weakly spinose, outer ramus
distinctly the shorter. Uropod 3, outer ramus short, length
~60% stout inner ramus. Telson subrectangular, narrowing
slightly distally, apex broadly rounded.
Type material. Ishimaru (1984): Female "a" (3.4 mm)
Holotype; intertidal, Ohzuchi, Japan. Zoological Museum
collections. Faculty of Science, Hokkaido University.
Distribudon. Known from a single intertidal station, at
Ohzuchi, Iwata Prefecture, northeastern Japan.
Etymology. The species is named in named in honour
of Dr Shin-ishi Ishimam who has contributed very signifi-
cantly to knowledge of the marine amphipod fauna of Japan
and adja-cent regions.
Taxonomic commentary. Parapleustes ishimarui
appears most closely related to P. americanus but differs in
characters provided in the key (above).
Parapleustes americanus, new species
(Fig. 3)
Parapleustes pacifica (?) Austin, 1985: 592.— Barnard &
Karaman, 1991: 650 (part).
Material examined;
ALASKA.
Bering Sea: N. E. of St. Lawrence I., P. Slattery, Dive 2, July
9, 1980 - 2 females. Punuk I., 5 m dive, gravel, P. Slattery
coll., July 6, 1983 - 1 1 specimens, including females, males
and im.
SE Alaska, ELB Stn. A48, Icy Strait, sand and gravel at LW
level, June 17, 1948 - 5 females.
BRITISH COLUMBIA.
North-central coast: ELB Stn. H25 (Cox Pt. Inlet), 6 m
dredge, muddy sand, July 18, 1964 -7 im; H48 (Goose I.),
8 m dredge, sand, kelp, Aug. 5, 1964 -2 females. Paratypes
(slide mounts), CMN Cat. no. NMCC 1955-0082. Swanson
Bay, C. Levings Stn. 51B-031, Apr. 4, 1973 - 1 im.
Vancouver I., north end: ELB Stn. V20 ( Brown Bay), coarse
sand at LW, June 22, 1959 - 1 female ov, Holotype (slide
mount), CMN Cat. no. NMCC 1995-0081.
Vancouverl., Southend: ELB Stns.,July5, 1976: B 16 (off
Bordelais L), 44-50 m dredge, sand and gravel- 4 females
ov.; B20 (off Long Beach, Trevor Channel), 30 m dredge,
gravel - 2 females ov.
Diagnosis. Female ov (3.0 mm): Head, eye medium
large, nearly round, black. Antenna 1, peduncular segment
2 long, length nearly equal to segment 1; flagellum 15-
segmented. Antenna 2, peduncular segments 3 & 4 slender,
subequal; flagellum 10-segmented.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
73
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
either side of pronounced dactyl-tip depression; dactyl
slender, with short terminal nail. Gnathopod 2 closely
similar, propod slightly smaller.
Peraeopods 3 & 4 slender, segment 5 long (~ segment 4)
marginal spines slender; dactyls medium long. Peraeopods
5-7 slightly increasing in size posteriorly; bases medium
broad, postero-distal lobes medium deep, hind margins gently
convex; distal segments slender, segment 5 long (~ segment
4); dactyls medium.
Pleon plate 3, hind comer with small hook. Uropods
slender, spinose. Uropod 1, outer ramus slightly the shorter.
Uropod2, outer ramus distinctly the shorter. Uropod 3, outer
ramus short, length -60% slender inner ramus having 5=4-
5 pairs of marginal spines. Telson narrowing gradually to
subacute apex.
Distribution. From the Bering Sea, and southeastern
Alaska to southern British Columbia, subtidally to depths of
50 m at southern locations, mainly on coarse sand and gravel
bottoms.
Etymology. The species name alludes to its distribution
along the American coast of the North Pacific Ocean.
Taxonomic commentary. In most character states,
including the gnathopod propods and the unshortened segment
5 of peraeopods 3 & 4, Parapleustes americanus is similar
to Ae type species, P. gracilis, from the North Atlantic
region. These two species had been synonomized by Barnard
6 Karaman (loc. cit.). However, in Parapleustes americanus,
the hind cusps of coxae 1-3 are more pronounced, urosome
2 is nearly occluded dorsally and, in uropod 3, the inner
ramus is relatively short.
Some morphological differences have been noted
between material from the Bering Sea and from southern
parts of its range in British Columbia. These are here
considered regional variations, not of species significance.
Chromopleustes, new genus
Parapleustes Stebbing 1906: 312 (part).— Gurjanova, 1951:
648(part).— Barnard 1969a: 425 (part).— Barnard & Karaman,
1991: 649 (part).
Parapleustinae: oculatus group, Bousfield & Hendrycks
1994:42.
Type species. Parapleustes oculatus Holmes, 1908.
Species composition. Chromopleustes johanseni, Gurj-
anova, 1951; C. lineatus, new species (p. 78).
Etymology, a combining form of the Greek ^^kromos"'
referring to the remarkably disruptively banded and striped
external body colouration, and the generic name “Pleustes".
Diagnosis. Body smooth above. Head, rostrum very
short; inferior antennal sinus short, nearly right-angled.
Eyes large, nearly round. Antennae well-developed, slender,
very weakly setose and/or spinose; flagella elongate. An-
tenna 2 distinctly the shorter; accessory flagellum extremely
minute or lacking.
Mouthparts strongly modified. Upper lip deeply
notched, lobes markedly asymmetrical. Lower lip very
wide, deep, outer lobes slender, rounded very oblique.
Mandible, left incisor with numerous (>15), right incisor
with 9-12, dentations or serrations; left lacinia multicuspate
(>20); blades tall, slender, numerous (10-15), some with
basal “satellite” setae; palp segments relatively short, segment
2 medially sparsely setose. Maxilla 1, apical spines of
outer plates numerous (13-17), slender tall; inner plate with
single minute apical seta; palp distally widened, with 6-8
apical spines and several closely subapical setae. Maxilla 2,
inner plate not broadened, inner marginal plumose setae
slender. Maxilliped, segment 3 (outer plate segment)
strikingly enlarged, much longer and larger than palp segment
1; segments 2 & 3 short, dactyl strong; inner plate with 2-3
stout inner marginal setae.
Coxal plates medium, little (or not) deeper than corre-
sponding body plates; coxa 1 not broadened or bent distally;
postero-distal notch single, minute. Gnathopods small to
medium strong, distinctly sexually dimorphic; propod and
carpus elongate (especially in female), shorter, broader and
stouter in male; palm of propod much shorter than posterior
margin, straight, oblique, lined with short setae, lacking
median tooth; carpal lobe shallow, medium to broad.
Gnathopod 1, basis with proximo-posterior “hump”.
Peraeopods 3-7 stout, medium long, weakly spinose,
segment 5 strong; dactyls short, strong. Peraeopods 3 & 4,
margins weakly spinose, lacking special setae. Peraeopods
5-7 regularly homopodous, bases somewhat narrowed be-
hind.
Pleon side plates very broad, medium deep, hind corners
acuminate but not produced. Pleopods normal, strong, not
sexually dimorphic. Urosome short, segment 2 not occluded
dorsally. Uropods regularly spinose; rami of uropods 1 & 2
distinctly longer than respective peduncles; outer ramus
slightly the shorter. Uropod 3, rami much longer (3X) than
peduncle, outer ramus distinctly the shorter. Telson med-
ium-long, rounding apically. Coxal gills large, platelike.
Taxonomic commentary. Within the subfamily
Parapleustinae, the genus Chromopleustes appears to be
closest morphologically to the genus Incisocalliope, on the
apomorphic side, and to Gnathopleustes on theplesiomorphic
side. It is distinguished from the latter, however, rather
superficially by the more slender antennae; longer, less
spinose legs with shorter dactyls; more elongate uropods,
and more striking, disruptive body colouration. In detailed
characterization, itis most distinct (unique) in the form of the
mouthparts, with specialized proliferation of pectinate spines,
blade spines, and multi-dentate incisors and lacinia mobilis.
To date, members of the genus have not been recorded
outside the North Pacific coastal marine region, on both
Asiatic and N. American coasts.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
74
KEY TO KNOWN SPECIES OF CHROMOPLEUSTES
1 . Eye small, remote from anterior head margin; antenna 2, flagellum <30-segmented; uropod 3, inner
ramus with few (4-5) pairs of marginal spines; maxilliped, palp segment 1 longer than 2; Asiatic Pac-
ific C. johanseni (p. 77)
— Eyes large, near anterior head margin; antenna 2, flagellum >30-segmented; uropod 3, inner ramus with
8-10 pairs of marginal spines; maxilliped, palp segment 1 shorter than 2; North American Pacific . . 2.
2. Gnathopod 2, propod slender (both sexes), length >2X depth; telson elongate, length >2X width; mand-
ible, left lacinia with about ~40 marginal teeth; maxilliped, inner plate with 3 inner marginal setae;
telson elongate, length >2X width C. oculatus (p. 74)
— Gnathopod 2, propod stout (both sexes), length <2X depth; telson short, length -1.5 X width; mandible
left lacinia with about 20 marginal teeth; maxilliped, inner margin with stout single blade adjacent to
facial seta; telson short, length -1.5 X width C. lineatus (p. 78)
Chromopleustes oculatus (Holmes)
(Fig. 4, 5, 6, 7)
Neopleuste^ oculatus Holmes, 1908: 531, figs. 36, 37.
Parapleustes oculatus Barnard & Given, 1960:1. — Barnard,
1969b: 198 (key).— Bousfield, 1985: 31, fig. 1.— Staude,
1987: 379.— Barnard & Karaman, 1991: 650.
Material examined: Nearly 60 specimens in 15 lots
ALASKA, (numbers of specimens in parentheses):
Bering Sea: Amchitka I., Aleutians Ids., C. E. O’ Clair Sta.
IA-2, Oct. 23, 1972 - I im.
Southeastern Alaska, ELB Stns, 1961 : A3(70); A6(2); A1 8(2);
A57(l); A168 (8); A174 (13); A175 (31); Stn. A8 (Tongass
Narrows, opposite Ketchikan), rock and sand at LW, June 3,
1961 - 1 male (slide mount), (fig. ’d); female ov. (slide
mount),(fig’d specimen), + 15 male, female specimens.
ELB Stn. S19B1 (Kameno Pt., near Sitka), July, 1980 -1
male, 2 im.
K. E. Conlan Stns., 1989: Torch Bay, 4.6-13.7 m, June 18
- male, female; Baranof I., Whale Bay, 4.5 - 6 m, June 21 -
1 male; Bocade Quadra, 30.5 m dredge, June 27 - 3 females;
Frederick Sound, Brothers I., 5-6 m., P. Slattery coll.. Mar.
24, 1988 - 8 males, females.
BRITISH COLUMBIA.
Queen Charlotte Island, ELB Stns, 1957 : N2a (Parry Passage)
22 males, females; W8 (2); W15b(2). Naden Harbour, 9 m
dredge. Sept 16, 1955 -1 female.
North-central coast: ELB Stns, 1964: H3 (40); H5 (50);
H7(6); H12(14); H29 (15); H33(30); H50 (60); H53 (16);
H57 (2); H65 (7).
South-central coast: Sutton I., Sechelt Narrows, 15 m dive,
Neil McDaniel coll., July , 1978 - 1 male, 1 female, 7 im.
Vancouver I., north end: ELB Stns., 1959: 03 (15); 05
(9)07b (15); V20 (Brown Bay) (9); V5 (Nigei I.) (2).
Vancouver I., south end: ELB Stns. 1955: FI (1);F2 (1); F4
(3); P4 (9); P7 (2); ELB Stns., 1976: B4 (1); B5 (2); B8 (5);
B21b(l).
CALIFORNIA:
Off Del Mar, 20 m, R. Rosenthal coll., June, 1969 - 6 im.
Diagnosis. Male (8. 2 mm): Head, eye large, broadly ovate,
black. Antenna 1, flagellum with -60 small segments;
accessory flagellum minute. Antenna 2. peduncle 5 distinctly
longer than segment 4; flagellum with -45 small segments.
Upper lip, median notch V-shaped, half depth of labrum.
Lower lip, inner lobes very broad. Mandible, spine row with
14-15 slender blades; incisor cutting edge nearly straight,
with 25-1- teeth, strongest proximally; left lacinia, cutting
edge slightly concave, with -50 fine teeth; palp segment 3
with 12 pectinate inner marginal and 3 long terminal setae.
Maxilla 1, inner plate with single short apical setae; outer
plate with 12-13 slender apical spines; palp segment 2
slightly widening distally, with 8-9 apical short spines.
Maxilla 2, outer plate not wider than inner. Maxilliped , inner
plate medium, with 3 ordinary inner marginal setae and 5
small apical denticles; outer plate medium, apex obliquely
truncated; palp segment 1 shorter than 2.
Coxae 1-3 relatively narrow, lower hind comer of each
with minute cusp. Gnathopod 1, hind margin of basis with
distinct proximal “hump”; carpus short, slightly longer than
deep; propod slender, longer than deep; palm margin oblique,
convex, merging imperceptibly with hind margin, postero-
distal angle with 3+1 groups of short spines. Gnathopod 2,
carpus short, little longer than deep; propod slender, length
> 2X depth; palmar margin very oblique, merging with hind
margin, postero-distal angle with 4 groups of spines and 2
singly inserted spines.
Peraeopods 3 & 4 slender; segment 6 with 8- 1 0 posterior
margin spine groups; dactyls very short, little curved.
Peraeopods 5-7 closely homopodous in form and size; bases
not strongly broadened, lower hind lobes shallow; dactyls
very short.
Pleon plate 3, hind comer weakly acuminate. Uropods
1 -3 relatively long, inner ramus > peduncle, margins strongly
spinose. Uropod 3, inner ramus > 2.5 X peduncle, margins
with 10-12 serial spines. Telson linguiform, length ~2X
width, apex rounded.
Distribution. The species ranges from the Bering Sea
and southeastern Alaska, south through British Columbia, to
California, commonly from LW level to depths of 20 m, in
a variety of habitats, associated with Ulva and bryozoans.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
75
MXPD
FIG. 4.Chromopleustesoculatus (Holmes, 1908). Female (11.0 mm). Monterey Bay, California.
(modified from Holmes, 1908)
FIG. 5, Chromopleustes sp. 1. (Barnard & Given,
(after Barnard
1960). Female (6. 5 mm). Santa Monica Bay, 70 m.
& Given, 1960)
Taxonomic commentary. The present female speci-
mens compare closely with the 11.0 mm female illustrated
by Holmes (1908) from Monterey Bay (Fig. 4). However,
they differ from the small mature female illustrated by
Barnard and Given (loc. cit.) from Santa Monica Bay, south
of Point Conception, California (Fig. 5). The latter has
relatively short antennal flagella, larger and broader coxal
plates 1 -4, broader bases of peraeopods 5-7, relatively weakly
spinose uropodrami, relatively short telson, and much longer
inner plate of the maxilliped. In order to clarify its taxonomic
status, re-examination of the Santa Monica Bay material
would seem desirable.
Chrompleustes oculatus displays a disruptive “saddle
back” colour pattern, with dark vertical stripe and bright yel-
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995 76
FIG. 6. Chromopkustes oculatus (Holmes) Male (8.2 mm); female ov (11.0 mm). Tongass Chan., Alaska
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
77
FIG. 7. Chromopleustes oculatus (Holmes). Male ov (8.2 mm). Tongass Channel, Alaska.
low spot on coxa 4 (see Bousfield, 1985, fig. 1), that is one
of the most striking of all subhttoral North Pacific amphipods .
The "saddle back" spot is wide, extending fully over the dor-
sum of peraeon segments 5 & 6, but only over segment 5 and
half of segment 6 in C lineatus. In C. oculatus, moreover,
there are 3 dorso-lateral body stripes on each side, vs. 4-5 in
C. lineatus, and coxal plates 1-3 are white, vs. brownish and
vertically striped in C. lineatus (p. 81).
As noted elsewhere (Bousfield & Hendrycks, 1994),
such may be a form of warning colouration, indicating the
presence of terpenes or similar body chemicals that are
distatefiil to fishes and other potential predators.
Chromopleustes johanseni (Guijanova)
(Fig. 8)
Parapleustes johanseni Guijanova, 1951: 550, fig. 446.
Parapleustes oculatus Barnard & Karaman, 1991: 650.
Ishimaru, 1994: 54
Diagnosis, (after Gurjanova, 1951): Female (7.0 mm).
Head, eyes relatively small, rounded, brownish, remote from
the anterior margin by an eye width. Antenna 1 slightly
Shorter than antenna 2; flagellum 21-segmented. Antenna 2,
flagellum 26-segmented.
AMPHIPACIFICA VOL 11 NO. 1. AUG. 31, 1995
78
FIG. 8. Chromopleustes johanseni (Gurjanova). Female (7.0 mm). Bering Sea. (after Gurjanova, 1951).
Mandible, spine row with about 20 slender blades; right
incisor, cutting edge with 12 teeth, largest proximally; palp
segment 3 with 6-8 pectinate “D” spines. Maxilla 1, inner
plate narrowly lobate, lacking apical seta; outer plate with 9
apical spines; palp segment 2 inner margin bulging inward,
apex with 4 stout spines. Maxilliped, inner plate very short,
apex setose; outer plate short, apex obliquely truncate; palp
segments 1 and 3 longer than 2 .
Gnathopods slender. Gnathopod 1, basis stout, heavy,
posterior margin with strong proximal “hump”, anterior
margin richly setose; carpus large, longer than deep; propod
more slender and a little longer than carpus, length ~2X
depth, palm short, convex, oblique, postero-distal angle with
few spines. Gnathopod 2, carpus elongate, length > 2X
depth, posterior lobe shallow; propod more slender , slightly
shorter than carpus, palm convex and more oblique than in
gnathopod 1.
Peraeopods 5-7 homopodous, bases broad. Uropod 3,
inner ramus narrowly lanceolate, length ~2X peduncle , with
5-6 marginal spines; outer ramus short -60% of outer ramus,
with a few marginal spines distally.
Telson relatively short, length -1.5 X width, apex
broadly acute.
Distribution. Bering Sea and coast of Kamchatka,
subtidally on Alariafistulosa. Strictly Asiatic Pacific.
Taxonomic commentary. The species is plesiomorphic
in most character states but is distinct in the weakly spinose
rami of uropod 3, and very broadened palp of maxilla 1.
Chromopleustes lineatuSf new species
(Figs. 9, 10)
Parapleustes oculatus Bousfield, 1985, part.
Material Examined. About 25 specimens in 10 lots:
ALASKA.
Southeastern Alaska: ELB Stn. A171 (Puffin Bay, Baranof
I.), rock and algae at LW level, July 25, 1961 - 22 im.; ELB
Stns., July, 1980: S7B1 (Dry Pass, Chichagof L), under
boulders, algae, LW - 1 female; SllBl (Column Pt.,
Lisianski Strait), bedrock and kelp atLW, July 30, 1980 - -50
specimens including males and females.
BRITISH COLUMBIA.
North-central coast: ELB Stn. N1 (Rivers Inlet), bedrock.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
79
FIG. 9. Chromopleustes lineatus, new species. Male (7.5 mm); Female ov (9.0 mm) Ahous Bay, B. C.
I.), bedrock, Phyllo-spadix, sand, at LW, Aug. 18, 1959 -
male (7.5 mm), Holotype (slide mount), CMN Cat. no.
NMCC1995-(X)71; female ov (9.0 mm). Allotype (slide
Phyllospadix, and coarse sand at LW, Aug. 3, 1959 - 25
specimens, including males, females, im.
Vancouver I., north end: ELB Stn. 05 (Ferrer Pt. beach),
under bedrock and kelp at LW, July 20, 1959 - 6 males 2
females, 3 im.
Vancouver I., south end: ELB Stn. 012 (Ahous Bay, Vargas
mount), CMN Cat. no. NMCC1995-(X)72; 7 males, 3 females,
Paratypes, CMN Cat. No. NMCC1995-0073. ELB Stns.,
1975: P5c (Taylor I, Trevor channel), from ascidians and
AMPHEPACIFICA VOL II NO. 1. AUG. 31, 1995
80
sponges under large boulders at LW level, - 1 male. ELB
Stns., 1976: B7 (Broken Is., Trevor Channel), from sponges
under rock, LW level - 9 males 6 females, 6 im. ELB Stns.,
1977: Bllb (Wickaninnish Bay, south end), from sponges
and algae under steep bedrock walls at LW - 1 male, 2
females; B13 (Trevor channel, off Brady’s beach), 6-14 m
dredge, sand, stone, algae - 1 female ov (14 mm); B14
(Trevor channel, off Execution rock), 44-54 m dredge, sandy
mud, algae - 1 female ov.
CALIFORNIA.
Albion Cove, Mendocino Co., from Tealia species, 20 m
depth, T. Chess coll., Sept. 26, 1978 - 1 10 females, 20 males.
Diagnosis. Male (7.5 mm): Head, eye broadly ovate,
black in alcohol. Antenna 1, flagellum ~60-segmented;
accessory flagellum minutely subconical, with 3 apical
setae. Antenna 2, peduncular segment 5 little longer than 4;
flagellum ~35-segmented.
81
AMPHIPACIFICA VOL II NO. 1 . AUG. 31, 1995
^O.n.CommensipUus,escommensalU (Shoemaker). Female ov (5.5 mm). Point Barrow, Alaska.
(after Shoemaker, 1952).
t U v-cleft separating asymmetrical
lobes. Lower lip, inner lobes broad, flat. Mandible, spine
row with 11-13 slender blades plus supernumerary setae;
right incisor with 9, left incisor with 1 7 stout teeth; left lacinia
with ~20 teeth, distally smallest; palp segment 3 with 10
pectinate “D” spines (of Cole, 1980) and 3 longer apical
setae. Maxilla 1 , inner plate with single short apical setae;
outer plate with ~18 slender apical spines; palp segment 2
apically rounding, with 8-9 short spines. Maxilla 2, outer
plate broader than inner. Maxilliped, inner plate with large
inner marginal blade-like spine and 4 small apical denticles;
outer plate rounded apically; palp segment 1 shorter than 2
Coxae l-3relativelybroad,deep. Gnathopods distinctly
sexually dimorphic. Gnathopod 1 , posterior margin of basis
acking distinct proximal “hump”; carpus short, as deep as
long; propod relatively deep, length ~ 1.5 X depth, palm
oblique, nearly straight, postero distal angle with 4 groups of
spines extending onto posterior margin. Gnathopod 2 ,
propod very short, length distinctly less than depth; propod
larger than in gnathopod 1 , slightly broadening distally,
palm oblique nearly straight, posterior angle with 4 spine
clusters and adjacent single small spine on posterior margin;
dactyls with minute posterior marginal setules.
Peraeopods 3 & 4, segment 6 relatively short, hind
margin with 6-7 spine clusters. Peraeopods 5-7 homopodous
peraeopods 5 slightly the shortest; basis of peraeopod 5 less
broadly expanded than in 6 & 7; dactyls medium, gentlv
curved distally.
Pleon side plate 3 , hind comer acuminate ; uropods 1 &2
slightly shorter and less strong than in C oculatus\ inner
ramus of uropod 1 with 6-8 serial paired spines. Uuropod 2
Uropod 3, inner ramus, length ~-2X peduncle, margins with
8-9 serially paired spines
Telson medium, length 1.5 X width, apex subtruncate.
Female (9.0 mm): Slightly larger and heavier- bodied than
male. Gnathopod 1 . carpus slightly longer, length slightly
greater than depth; propod shorter, length ~ 1.3X depth.
Gnathopod 2 , carpus not shortened, length -1.5 X depth-
propod subrectangular, not broadening distally.
Distribution. From southeastern Alaska, through the
Queen Charlotte islands and north central mainland coast of
Bntish Columbia to Mendocino Co., northern California
oftenin association withsponges,coelenterates and tunicates’
on hard bottoms, from LW level in the north, subtidally to
depths of over 50 m in the south.
Etymology, from the Latin meaning lined, al-
luding to the fine, orange, dorso-lateral body stripes, and
vencal yellow stripes on brownish coxal plates 1 - 4 .
Taxonomiccommentary, Thespecies differs markedly
from C oculatus in colour, and from C. johanseni in char-
acters of the key (p. 74), and additonally in the highly
modified mouthparts, especially the mandible and maxilla 1 .
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
82
Commensipleustes, new genus
Parapleustes Shoemaker, 1952: 231. — J. L. Barnard, 1969a:
(partim). — Barnard & Karaman, 1991: 650.
Type specis. Parapleustes commensalis Shoemaker, 1952:
231, fig. 83. (see Fig. 11).
Diagnosis. Head, rostrum about equal to rounded
anterior lobe. Eyes medium large, black. Antennae slender,
peduncles short, flagella short (<15 segmented).
Upper lip, medium notch shallow, lobes slightly
asymmetrical. Lower lip inner lobes deep medium wide,
rounded; outer lobes small, ovate, oblique. Mandible, molar
process relatively strong, apex slightly triturative(?); spine
row with numerous (10+) blades; left lacinia 10-dentate;
palp segment 3 slender, with 2 inner marginal pectinate “D”
spines. Maxilla 1, inner plate small, with single apical seta;
palp segment 1 lacking shoulder seta(e) segment 2 stout,
apex obliquely rounded, with 8 short spines, and a facial row
of 3 setae. Maxilla 2 , inner plate regular, with single inner
marginal plumose setae. Maxilliped, inner plate with 3
apical “button” spines and 2 slender spines; outer plate, apex
with 2 slender spines, segment 3 lacking distal pectinations;
palp relatively short, curved.
Coxae 1-3 relatively narrow, 1 not expanded distally.
Lower margins gently convex, hind cusp minute. Coxa 4 not
broader than deep. Gnathopods medium strong, closely
subequal, not sexually dimorphic (?). Gnathopod 1, basis,
anterior margin strongly short-setose; hind margin weakly
so merus lacking distal process; carpus, hind lobe relatively
broad, rounded below; propod relatively short, not expanding
distally; palm oblique, convex, median tooth apparently
lacking.
Peraeopod 3 & 4, basis, antero-distal margin with short
setae; segment 5 short, length < segment 4; segment 6 stout,
hind margin distally with groups of stout spines against
which the dactyl closes, forming a grasping organ. Peraeopods
5-7 homopodous, short, stout; bases medium; segment 5
short; segment 6, anterior marginal spines and dactyl forming
a grasping organ, as in peraeopods 3 & 4.
Pleon plates 2 & 3, hind comers mucronate, slightly
produced. Uropods 1 & 2, relatively short, little or not
exceeding uropod 3. Uropod 3, inner ramus relatively long.
Telson linguiform, medium, distally narrowing to
rounded apex.
Distributional ecology. Commensipleustes commens-
alis, the only known species, occurs on pleopods of the spiny
lobster, Panulirus interruptus, off Santa Barbara, CA. Also
recorded by Wicksten (1982) off southern California.
Taxonomic commentary. The prehensile peraeopods,
in combination with the short peraeopodal segment 5,
unexpanded coxa 1, and specialized mouthparts are here
deemed sufficient for separate generic recognition.
Gnathopleustes, new genus
Parapleustes Guijanova, 1972: 131 (part).— Barnard, 1969b:
203 (part).— Barnard & Karaman, 1991: 649 (part).
Neopleustes Stebbing, 1906: 311 & 728 (part).
Parapleustinae, group 1 (part) Bousfield & Hendrycks,
1994: 42.
Type species. Iphimedia pugettensis Dana, 1853, original
description.
Species. Gnathopleustes serratus, new species (=
Parapleustes pugettensis Shocmdker, 1964); G. den (Barnard,
1969b); G. pachychaetus, new species; G. trichodus. new
species; G. simplex, new species.
Diagnosis. Body smooth above. Head, rostmm shorter
than bluntly rounded anterior lobe; inferior antennal sinus
broadly incised. Eyes medium large, subrotund. Antennae
well-developed; posterior margins often setose. Antenna 1
the longer, peduncular segment 2 short; accessory flagellum
minute, apex 2-3 setose. Antenna 2, peduncle strong,
flagellum often with special thickened setae.
Mouthparts strongly modified. UL shallowly notched,
lobes asymmetrical. Lower lip broad, outer lobes rounded,
oblique. Mandible: incisor regularly toothed; left lacinia 7-
10 dentate; blades 4-12 in number, stout, distally chisel-
shaped; molar body reduced, slender, apex fuzzy; palp
normal, segment 1 short, segment 2 medially setose. Maxilla
1, outer plate with 9 tall slender apical spines; palp with
subapical facial setae. Maxilla 2, inner plate little expanded;
maxilliped, palp strongly dactylate, segment 2 largest; outer
plate segment longer than palp segment 1, not enormously
developed; inner plate short, inner marginal setae numerous
(4-9).
Coxal plates wide, deeper than corresponding body plates;
coxa 1 broadened distally, hind margin spinose near basis,
postero-distal notch single, small. Gnathopods 1 & 2 large,
subequal (Gnathopod 2 larger), variously sexually dimor-
phic; basis stout, with antero-distal setal group; merus with
slight distal process; carpus, posterior lobe short, deep (esp-
ecially in male); propods subovate, palms strongly oblique,
elongate, convex, palmar tooth distinct, near hinge; palmar
margin tending to be lined with special thickened or blade-
like setae; postero-distal angle with 2-4 groups of spines,
hind margin short, bare, or longer, setose.
Peraeopods 3-7 stout, spinose, normal; segment 5 strong,
moderately overhung proximally by segment 4; dactyls
medium strong, curved. Peraeopods 3 & 4, margins of
segments 4, 5 & 6 may bear special thickened setae.
Peraeopods 5-7 regularly homopodous, bases broad, convex
behind.
Pleon side plates broad, deep, hind comers acuminate but
not strongly produced. Pleopods strong, normal, not sexu-
ally dimorphic. Urosome short, segment 2 nearly occluded
dorsally. Uropods 1 & 2 regularly spinose; uropod 1, rami
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
83
KEY TO KNOWN SPECIES OF GNATHOPLEUSTES
moderately to strongly setose posteriorly; gnatho-
pods tending to strong sexual dimorphism, palmar margins heavily lined with blade-setae or split-tipped
°n^ f -50% length of antenna 1, flagellum ne^iy bare (short seMe'only);' gnathopods
pods slightly sexually dimorphic, palmar margins lined with relatively few normal setae 5.
margins heavily lined with split-tipped setae; mandible, blade
row of 10-12 unmodified blades; antenna 1 (male), flagellum brushy G. simplex, (p 87)
-Gnathopods (male), m^gms lined with “balloon" setae (pachychaete); mandible, blades (especially dist
a y) modified, antennal setation weak, with no distinct “brush” (setose on hind margin only) 3.
^'stronglyletotr'*' 5-7 all lacking marginal setae; gnathopod palms
-Antenna peduncles spinose and setose (flagella of A2 variously setose); peraeopods 3-4 oi ^7 sJonglv
setose behind; gnathopod palms strongly setose (with “balloon” setae) 4
4 . Gnathopod 2, palmar margin distinctly concave, postero-distal angle with 2 spine groups; peraeopods
■ti Q of segments 4-6 with clusters of long brushlike setae (male); uropod 3, outer ramus
with 6-9 nwgmal spines; antenna 1, peduncular segment 1 not elongate G. trichodus (p 91)
-Gnathopod 2. palmar margin nearly straight, postero-distal angle with 3-4 spine clusters; peraeopods 5-
7, hind m^gins of segments 4 - 6 with spine clusters only (lacking setae); uropod 3, margins of outer
ramus with 5-7 spines only; antenna 1, peduncular segment 1 long G. pachychaetus (p. 87)
5 Gnathopods, dactyls smooth behind; telson less than twice as long as wide; peraeopods 5-7, segment 5
^stinctly shorter than 4, strongly overhung posteriorly by segment 4 G, pugettensis (p. 83)
Gnathopods, dactyls postenorly finely serrate; telson elongate, at least twice as long as wide; peraeo-
pods 5-7, segments 4 & 5 subequal in length, 5 normally overhung by 4 G serratus (p 91)
subequal; uropod 2, outer ramus the shorter. Uropod 3, outer
ramus distinctly the shorter. Telson elongate, narrow-
ingdistally; dorsal penicillate setae about mid-point from
base. Coxal gills large, broad.
Taxonomic commentary. Members of Gnathopleustes
overlap to considerable degree with members of Inciso-
calliope . However, the two genera are maintained as distinct
units for the present because they can be keyed, and the
distributions are discreet. Within Gnathopleustes, two main
subgroups Can be distinguished, as outlined in the key below.
In the more advanced members (G. pugettensis, G. den, G.
simplex) the gnathopods appear very slightly sexually dimor-
phic, and the mouthparts, peraeopods and uropods are apo-
morphic.
Parapleustes pugettensis Barnard, 1969b: 203.— Austin,
1985:592. — Staude, 1987:379. — Barnard &Karaman, 1991-
650.
TmJncisocalliope newportensis Barnard, 1959: 22.
1^ Parapleustes pugettensis Barnard & Given, 1960:43.
— Ishimaru, 1984: 19.
Material examined. 258 specimens in 38 lots-
ALASKA.
Southeastern Alaska. ELB Stns, June- July, 1961: A40 (4 +
slide mount); A80 (1); A164 (1); A171 (1).
BRITISH COLUMBIA.
Queen Charlotte Islands. ELB Stns., July-August 1957-
Wll (6) W15b(l).
Distributional commentary. Members of the genus are
restricted almost entirely to the Pacific coast of North America,
from southeastern Alaska to southern California!
Gnathopleustes pugettensis has been reported, but not
confirmed, from Japanese waters by Irie & Nagata (1962).
Gnathopleustes pugettensis (Dana)
(Fig. 12, 13)
Iphimedia pugettensis Dana, 1853: 932, pi. 63, fig. 6.
Neopleustes pugettensis Stebbing, 1906:728.
North-central coast, ELB Stns., July, 1964- H43 (!)• H53
(1);W64(2).
Northern and central Vancouver I.: ELB Stns., 1959: HIO
(40 specimens including males and females); N16 (1); V4b
(Hope I., Roller Bay), under boulders, kelp, Phyllo-spadix,
at LW level - male (slide mount) (fig'd specimen); female
(slide mount) (fig'd specimen) + 8 other specimens; VIO(IO)-
V17(1);V19(1).
Southern Vancouver I.: ELB Stns., 1955: P9(l) ELB Stns
1970: P702 (20); P707 (5); P710b (1); P714 (1); P719 (5,'
including females ov.). ELB Stns, 1975: P2 (25); P3a (1);
P5a (1); P5b (1). ELB Stn. B4 , off Brady’s Beach, 60-70 m
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995 84
FIG. 12. Gnathopleustes pugettensis (Dana). Male (4.0 mm). Southern California,
(modified from Barnard & Given (1960).
naturalist’ s dredge, sand and algae, June 25, 1976 - 2 females.
ELB Stns., 1977: B8 (5); B 14(1).
WASHINGTON-OREGON:
Strait of Juan de Fuca to Newport. ELB Stns., July-Aug.,
1966: W22 (30, including slide mount); W30 (1); W34 (1 1);
W35 (9); W36(8); W40 (19); W50 (30, + slide mount); W53
(1); W57(l); W63 (6);W66 (2).
Diagnosis. Male (6.0mm); Body relatively short, coxal
and pleon plates deep. Head, eye large, subrectangular.
Antenna 1 , peduncular segment 3 relatively long (1/2 segment
2); flagellum of 35-40 medium long segments; accessory
flagellum conical, apex with single long seta. Antenna 2,
peduncular segment 5 shorter than 4; flagellum with ~35
nearly marginally smooth segments.
Upper lip strong, asymmetrical. Lower lip, inner lobes
deep; outer lobes normally oval, oblique. Mandible, molar
short, blunt; spine row with 8-10 stout, abruptly acute
blades; incisor, cutting edge with 6 uneven teeth; palp seg-
ment 3 with 8 inner marginal pectinate spines; left lacinia
with 8 unequal teeth. Maxilla 1, palp segment 2 with 4
unequal apical spines. Maxilla 2, outer plate not narrowing
distally, apex strongly setose. Maxilliped, inner plate rel-
atively large, distally broad, with 7 distal facial setae, and 4
small apical marginal denticles; outer plate regular, apex
subtruncate; palp, dactyl slender, curved.
Coxae 1-3 relatively large, deep; coxa 5 deep. Gnathopod
1 , carpus medium, about as deep as long, carpal lobe medium;
propod smoothly ovate, palmar margin convex, very oblique,
postero-distal angle with groups of 4 and 3 spines and a
single spine distally on posterior margin; dactyl, hind margin
not serrated, with a few setules only. Gnathopod 2, carpus
and dactyl slightly larger, but proportions and armature
similar to that of gnathopod 1.
Peraeopods 3 & 4 relatively short, distal segments (4/6)
weakly marginally spinose; dactyls medium, > 1/3 length of
segment 6. Peraeopods 5-7 closely homopodous, 5 slightly
smallest; bases broadly expanded, hind margins convex;
distal segments (4-6) weakly marginal spinose, not setose;
dactyl medium.
Pleon plates 1-3 deep, broad, hind comer of 3 squared.
Urosome 2 occluded dorsally by 1 & 3. Uropods ordinary.
Uropod Lpeduncularpostero-distal spine strong. Uropod2,
outer ramus short, length ~2/3 inner ramus. Uropod 3 strong,
inner ramus >2 X peduncle, margins with 5 spines.
Telson subrectangular, length about 1.5X width, apex
truncate.
Female (5.5 mm): Gnathopods not described, presumably
slightly smaller and less setose than in male.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
FIG. U.Gnathopleustespugettemis (Dana). Male (6. 0 mm). RoMerBay. B. C
Distribution. From southeastern Alaska and northern
British Columbia south through Washington & Oregon to
Point Conception and Santa Barbara regions, subtidally to
70 m; replaced by /. newportensis south of Pt. Conception.
Taxonomic commentary. Gnathopleustes pugettensis
is the generic type and, in balance of character states, is most
advanced. Overall, it is closely similar to G. den and G.
simpleA.
Gnathopleustes den (Barnard)
(Fig. 14)
Parapleustes den J. L. Barnard, 1969b: 199, fig. 54 —
Staude, 1987: 319. — Barnard & Karaman, 1991: 650.
Material examined. Male (8.0 mm), Holotype, J. L.
Barnard Stn. 6, Allan Hancock Foundation Cat No. #559.
Material of this species was not found in the study range,
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
86
FIG. 14. Gnathopleustes den (J. L. Barnard). Male (8. 0 mm). Corona del Mar, California.
(after Barnard, 1969b).
despite its close similarity to G. pachychaetus.
Diagnosis (partly after Barnard 1969b). Male (8.0 m):
Body and coxal plates medium, ordinary. Head, eyes medium,
broadly short-reniform. Antenna 1, peduncular segment 3
medium, length 1/2 segment 2; accessory flagellum very
short, with 2 slender apical spines; flagellum elongate (59
segments). Antenna 2, peduncular segment 5 not shorter
than 4; flagellum with 50+ segments, proximally stoutest,
nearly bare.
Upper lip, apical cleft relatively deep, lobes nearly
symmetrical. Lower lip, inner lobes deep, outer lobes
steeply oblique. Mandible, molarprominent, apex subacute?;
spine row with 13-15 medium stout blades; left lacinia 9-
dentate; cutting edge of incisor with 6 irregular teeth; palp
segment 3 with 11-12 inner marginal pectinate “D” spines.
Maxilla I, palp, apex with 6-7 spines. Maxilliped, inner
plate with 1 marginal spines and 2 facial setae; outer plate
tall, columnar.
Coxal plates 1-3 large, deep, relatively narrow; coxae 1
distally expanding, 1-3 with 3-4 hind marginal spines; coxa
5, lobes medium deep. Gnathopod 1 , c£upus medium, length
and depth subequal; propod ovate, palmar margin shallowly
oblique, very slightly convex, densely finely setose,
continuous with hind margin, median tooth very weakly
developed; postero-distal angle with 3 groups of spines (?);
dactyl stout, hind margin smooth, not serrated. Gnathopod
2, propod distinctly larger and deeper than in gnathopod 2 ;
palm nearly horizontal, nearly straight, densely finely setose,
with weak median tooth, postero-distal angle with 3 groups
of spines, a single distal spine on the posterior margin; dactyl
stout, smooth behind.
Peraeopods 3 & 4 strong; segment 6, hind margin with
6 spine groups; dactyl short. Peraeopods 5-7 relatively stout;
bases slightly broadest distally, hind margins nearly straight,
weakly crenulate; segment 4 broad, width -2/3 length;
segment 6, margins spinose (not setose); dactyls medium, -
1/3 length of segment 6.
Pleon plate 3, hind comer acuminate. Urosome2 with
free dorsal margin. Uropods 1 & 2 stout, rami relatively
short, not extending beyond uropod 3; uropod 2, rami
subequal. Uropod 3, inner ramus with 6-7 pairs of marginal
setae.
Telson subrectangular, length ~ 2X width, apex
subtruncate.
Female (10.0 mm); Undescribed.
Distribution. Known only from the type locality at
Corona del Mar, south of Pt. Conception, California, in
washes of tubes of the polychaete Phragmatopoma sp., at
LW level.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
87
Taxonomic commentary. The type male specimen,
figured by Barnard (1969b), differs from G. pachychetus in
lacking posterior marginal setae on the peduncle of antenna
1, and in lacking brush setae on the flagellum of antenna 2.
Gnathopleustes simplex, new species
(Fig. 16)
Material examined.
BRITISH COLUMBIA:
Southern Vancouver Island: Off Wouwer I., Barkley Sound,
P. Lambert coll., June 29, 1973 - male Holotype (6.8 mm)
RBCM loan No. 973-156.
ELB Stn P17d, Kirby Pt. Bay, Diana I., under-rock habitat
among sponges, tunicates, at LW, Aug. 6, 1975- 1 female
ov. (5.0 mm).
Diagnosis. Male (6.8 mm). Body slender coxal and
pleonal plates relatively small, shallow. Head, eye medium
small, broadly reniform. Antenna relatively short, 1 slightly
longer than 2. Antenna 1 , peduncular segment 3 short, length
1/2 segment 2; accessory flagellum minute, conical; flagellum
with 35 segments, nearly devoid of marginal setae. Antenna
2, peduncular segments 4 &5 short, 5 slightly longer, both
with facial clusters of setae; flagellum of 30 weakly brush-
like segments, basally stoutest, each with distal cluster of
short setae.
Mandible, molar small apically conical; spine row with
10-11 slender blades and a few supernumerary setae; cutting
edge of incisor with 6 variably sized teeth; palp segment 3
short, inner margin with 1 1 pectinate “D” spines; leftlacinia
with 12(?) teeth. Maxilla 1, palp slender with 4 apical slender
spines? Maxilla 2? Maxilliped, inner plate short, broadest
medially, with distal facial setae, and 4? apical marginal
spinules; outer plate relatively short, distally narrowing,
apex rounded; palp, dactyl curved.
Coxae 1-4 medium, 1 & 2 each with 2-3 posterior
marginal spines. Gnathopod 1, basis with antero-distal
marginal setae; carpus short, deeper than long, hind lobe
distally broad; propod short ovate, relatively deep, palmar
margin shallowly oblique, nearly straight, moderately
marginally simple-setose, with distinct median tooth, postero-
distal angle with cluster of 3 spines, posterior margin with
single distal cluster of 2 spines; dactyl smooth behind.
Gnathopod 2 similar, but large; basis with fewer antero-
distal setae; carpus, hind lobe slightly broader; propod more
elongate, palmar margin slightly concave; postero-distal
angle with cluster of 3 spines; hind margin strongly setose,
with distal cluster of 3 spines; dactyl smooth behind.
Peraeopods 3 & 4 ordinary, not setose; dactyls medium.
Peraeopods 5-7 bases not strongly broadened, hind margins
nearly straight; segment 4 short; segments 4-6 anterior and
posterior strongly spinose and setose; segment 6, anterior
margin with 6-7 clusters of spines and setae; dactyls medium.
Pleon plate 3 weakly spinose below, hind corner
acuminate. Urosome 2 occluded dorsally by segments 1 &
3. Uropod 1 , rami not elongate, weakly spinose marginally.
Uropod 2, outer ramus distinctly the shorter. Uropod 3
regular(?). Telson medium, narrowing distally 7 to sharply
rounded apex.
Distribution. Known only from Barkley Sound,
Vancouver I., British Columbia, LW and shallow subtidally,
associated with sponges and tunicate, under rocks.
Etymology. From the Latin “simplex”, meaning simple,
not ornate, with reference to the unshortened, unbroadened
blades of the mandibular spine row.
Taxonomic commentary. Gnathopleustes simplex
encompasses some plesiomorphic character states (e.g., slen-
der mandibular blades) but, in balance of character states, is
apomorphic. It appears not unlike G. pugettensis and the
more southerly G. den, in the form of the antenna and other
features of the mouthparts, especially the maxilliped.
Gnathopleustes pachychaetus, new species
(Figs. 17,18)
Material examined.
ALASKA.
Southeastern Alaska. ELB Stns., June-July, 1961: A6 (1);
A8(4 + slide mount); ABO (4); A171 28 + slide mount).
ELB Stns, July, 1980: S4B4 (2); SllBl (2); S18B1 (!)•
S22F1 (1).
BRITISH COLUMBIA.
Queen Charlotte Islands. ELB Stns., July- August, 1957: E21
(3); W9 (4). Flamingo Harbour, Stn. 3539, July 17, 1935 -
4 females ov; J FRB Stn. Ml-65-55, DBQ, JWS coll., Aug.
6, 1965 - 1 female ov.
North-central coast, ELB Stns., July, 1964: H35 (-lOO)- H39
(15); H40 ~70); H41 (-25).
Northern and central Vancouver I.: ELB Stns, July, 1959:
05 (-15); 017 (7); N18 (17, incl. males and females). R. M.
O’Clair Stns, 1976: #760007, Kelsey Bay (1 male; #
760023, Squirrel Cove, Cortez I. - 30 males and female (+
slide mount); #760046, Port Hardy - 1 female ov.
Southern Vancouver I.: ELB Stns, July-August, 1955: P4
(~15); P6a(-40)P6c(-15);F5 (-15); Ml 1 (-30). ELB Stns,
1970; P704 (1); P702 (1); P707 (-25); P708 (1). ELB Stns,
1 975 : P 1 7d ( 1 female + slide mount); P5c (5); P20a ( 1 ); P20c
(2). ELB Stns., 1976: B 1 (10); B2 (6); B4 (9); B5 (44); B7 (2);
B8(l);B12b(-160+ slide mounts); B 1 3 (-30)B28 ( 1 ). ELB
Stns, 1977: B6a (3); B8 (1): B1 la (1); Bllb (2); B13 (1); B
19b(2). R. M. O’Clair Stns., 1976: #760028, Sturdies Bay,
Galiano I. - 9 males Sc females. # 760031 Miner’s Bayi
Mayne I. (-30 males, females). #760034, Horton Bay, Mayne
I., June 22, 1976 - Male (6.8 mm), Holotype (slide mount),
CMN Cat. no. NMCC 1995-0076; female (5.8 mm). Allotype
(sUde mount), CMN Cat. no. NMCC 1995-0077, -i- 8 males,
12 females, Paratypes, CMN Cat. no. NMCC 1995-0078. ’
Ogden Pt. breakwater, Victoria, R. J. Long coll., 1976 - 2
females, 1 male.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
88
FIG. 16. Gnathopleustes simplex, n.sp. Male (6.8 mm); female ov (5.0 mm). Barkley Sound, B. C.
WASHINGTON-OREGON.
Coastal Stations, ELB, July-August, 1966: W2 (4 + slide
mount); W5 (2); W22 (9 + slide mounts); W24 (-300); +
slide mounts); W34 (15) W45 (9); W50(~50); W53 (10);
W57 (-25); W58 (-28); W61 (23); W63 (-70).
Eagle Cove, San Juan I., R. M. O’Clair Stn. 74001, June 21,
1974 - 2 females (slide mount).
Charleston, Ore., mouth of Coos Bay, floating dock below
LW, among Enteromorpha and Polysiphonia sp., K. E.
Conlan coll., July 8, 1986: Stn 07- 1 - -70 males, females, im;
Stn. 08-23 - 3 females, 4 im.
Diagnosis. Male (6.8 mm): Body slender, coxal and pleonal
plates medium deep. Head, eye relatively small, short-
reniform. Antenna 1 , peduncular segments each with posterior
marginal clusters of long setae; segment 3 long, length -2/
3 segment 2; accessory flagellum cone-like, with strong
apical seta; flagellum with 48 segments. Antenna 2 shorter
than 1; peduncular segment 5 not shorter than 4, both with
posterior and facial clusters of setae; flagellum relatively
short, with -40 short segments, brush-like posteriorly.
Upper lip tall, apical cleft shallow, lobes asymmetrical.
Lower lip, inner lobes deep; outer lobes large, ovate, strongly
oblique. Mandible, molar small apex subacute; spine row
with 8-9 short thick blades, cutting edge of incisor with 7
regular teeth; palp segment 3 narrowing distally , inner margin
with 1 8 pectinate “D” setae; left lacinia with 8-9-dentate.
Maxilla 1, palp slightly narrowing distally, with 5 apical
spines. Maxilla 2, outer plate narrowing distally apex
relatively sparsely setose; inner plate with stout median
marginal setae. Maxilliped, inner plate broad, with 7 distal
facial setae and 5 apical marginal spinules; outer plate tall,
columnar, apex rounded; palp segment 3 large stout, palp
slender curved.
Coxal plates 1-3 each with single posterior marginal
spine. Gnathopod 1, carpus shorter, deeper than long;
propod ovate, narrowing distally, palm nearly horizontal
with distinct median tooth, and dense clusters of long thick
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
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90
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
Fig. 18. Gnathopleustes pachychaetus, new species. Male (6.8 mm). Mayne I., B. C.
marginal "balloon" setae, margin merging smoothly with
posterior margin, spine group at postero-distal angle with 4
spines, outermost largest, posterior margin with single distal
cluster of 3 spines; dactyl, hind margin with a few small
setules. Gnathopod 2 very similar but slightly larger, carpal
lobe slightly deeper; palmar margin relatively short , distally
slightly concave, postero-distal angle, spine cluster with 4
spines, posterior margin distally with a single spine and
single cluster of spines.
Peraeopods 3 & 4, segment 4-6 with dense clusters of
spines and setae especially posteriorly; dactyls medium.
Peraeopods 5-7 similar, bases slightly broadening distally,
hind margins gently convex; segment 5 short, segment 6
long, margins spinose, not setose; dactyls medium.
Pleon plates 2 and 3, lower margins weakly spinose,
hind comers acuminate, slightly produced. Urosome 2
occluded dorsally by segments 1 &3. uropods 1 & 2 slender,
slightly exceeding uropod 3 . Uropod 2 , outer ramus distinctly
shorter than inner ramus. Uropod 3 , inner ramus with 6 pairs
of marginal spines, outer ramus relatively large, = 3/4 inner
ramus, margins 5 -spinose
Telson broadly linguiform, apex broadly rounded.
Distribution. From southeastern Alaska, commonly
throughout B. C. coastal waters, to southern Oregon, under
rocks and among algae at LW level to shallow subtidal.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
Etymology. From the Greek root words "pachy",
meaning thick, and '"chaite" meaning hair, in reference to the
thick, broad, laminate setae comprising the setose armature
of the gnathopods.
Taxonomic commentary. Gnathopleustes pachy-
chaetus is somewhat similar to the more southerly species,
G. den, in the strongly setose, weakly sexually dimorphic
gnathopods, and in some mouthparts (e.g., mandibular
blades). However, the gnathopod setae are more strongly
thickened, and thick setae occur also on the distal se gm ents
of the peraeopods, especially in the male. The posterior
margins of peduncular segments of antenna 1 have 6-8 clust-
ers of strong setae, and the flagellum of antenna 2 is brush-
like, whereas corresponding parts of G. den are bare.
Gnathopleustes trichodus, new species
(Fig. 19)
Material Examined.
BRITISH COLUMBIA.
Southern Vancouver I.; West of Amphitrite Point, N. A.
Powell Stn 67-83, 22 m, Aug. 22, 1967 - male Holotype
(slide mount) CMN Cat. no. NMCC 1995-0083.
Diagnosis. Male (8. 5 mm): Body slender, coxal and
pleonal plates medium deep. Head, eye broadly reniform,
black. Antenna 1 shorter than antenna 2; peduncular
segment 3 short, length< 1/3 segment 3; accessory flagellum
conical, with 1 large apical setae; flagellum with 55 segments
basally slightly short-setose. Antenna 2, peduncular segment
5 longer than 4, both with distal and facial clusters of setae;
flagellum elongate, with -50 segments, each with prominent
distal whorl of short setae.
Upper lip, median notch shallow, lobes nearly
symmetrical. Lower lip, inner lobes relatively shallow, outer
lobes regularly ovate, oblique. Mandible, molar process
prominent, apex subacute; spine row with 9 medium stout
blades, tips obliquely acute; cutting edge of incisor with 6
irregular teeth; palp segment 3 slender, elongate, with 13
inner marginal pectinate “D” spines; left lacinia9- 1 0 dentate.
Maxilla 1 , palp slender, with 4 apical spines. Maxilla 2, outer
plate distally narrowing, apex strongly setose. Maxilhped,
inner plate short,, with 7 distal facial setae and 5 apical
marginal short spines; outer plate short narrowing to
subtruncate apex; palp segment 3, inner margin with pectinate
setae, dactyl slender, nearly straight.
Coxal plates 1-3 relatively broad, each with 1-3 hind
marginal short spines, coxa 4 very broad, width and depth
subequal. Coxa 5 shallow. Gnathopod 1, carpus short,
deep>er than long, lobe narrow; propod, palmar margin straight
or slightly concave, median tooth strong, postero-distal
angle with 2 groups of spines; median face with numerous
clusters of slender thickened setae, giving densely setose
appearance to propod; dactyl strong, not serrated behind.
Gnathopod 2, similar, larger, very heavily setose; palm of
propod distinctly concave; dactyl stout, nearly smooth behind.
Peraeopods 3 & 4, stout, margins of segment 4-6 setose
and spinose; dactyls strong, >1/3 length of segment 6.
Peraeopods 5-7 subsimilar, bases regularly broadly ovate,
smooth behind; segment 4-6 hind margins strongly setose
and spinose; segment 4 relatively short; dactyls medium.
Pleon plate 3, lower margin weakly spinose, hind comer
acuminate, slightly produced. Urosome 2 nearly occluded
dorsally by segments 1 & 3. Uropods slender, elongate.
Uropod 1, distal peduncular spine short. Uropod 2, outer
ramus slightly shorter than inner ramus. Uropod 3 inner
ramus slender, margins with 8 pairs of spines; inner ramus
relatively long, with 5-6 pairs of marginal spines.
Telson linguiform, medium long, apex broadly rounded.
Distribution. Known only from the type locality near
Amphitrite Pt., outer coast of southern Vancouver Island.
Etymology. From the Greek “trichos” mean hair,
alluding to the dense setation of the gnathopods and
peraeopods.
Taxonomic commentary. Gnathopleustes trichodus
is a primtive species, phyletically isolate from others of the
group, especially in the form of the mouthparts, relative
lengths of the antennae, broad coxal plates, concave gnatho-
pod palms and densely setose peraeopods.
Gnathopleustes serratus, new species
(Figs. 20,21)
Parapleustes pugettensis Shoemaker, 1964: 410, fig. 10.
Material Examined. About 40 specimens in 15 lots:
ALASKA. Southeastern Alaska. ELB Stns, 1961: A75
(Kayak, Wingham I.), LW, under boulders, June 27 - 5 males
3 females.
BRITISH COLUMBIA.
Queen Charlotte Island. ELB Stns, 1957: W12a(3);Hll(l);
Stn HI 4a, Yakan Pt., Graham I., under boulders atLW, Aug.
25 - male (8.7 mm), Holotype (slide mount) CMN Cat. no
NMCC 1995-0068; female ov. (10.0 mm) Allotype (slide
mount), CMN Cat. no. NMCC 1995-0069; plus 10 males, 9
females, 1 im.,Paratypes,CMNCat.no.NMCC1995-0070.
Northern Vancouver L: ELB Stns N1 (Open Bight, Rivers
Inlet)(5);V5(NigeiL,)(2).
Southern Vancouver I.: ELB Stn. 015 (Box I, north end
Wickaninnish Bay) (20); ELB Stn P719 (Cape Beale), 1970
- 1 male, 1 im. ELB Stn. B3 (Diana L, Trevor Channel), 1976
- 1 female. ELB Stn B6a (Trial I. Point, Victoria), 1977 - 4
specimens
WASHINGTON-OREGON.
ELB Stns, 1966: W 40 (4); W57 (2); W58 (4); W61 (1); W63
(Cape Kiwanda) (>100).
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
92
FIG. 19. Gnathopleustes trichodus, new species. Male (8.5 mm). West of Amphitrite Pt., V. I., B. C.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
93
FIG. 20. Gnathopleustes serratus n. sp. Female (9.0 mm). Dillon Beach, CA. (after Shoemaker, 1964).
CALIFORNIA.
Albion Cove, at Cone Rock, Mendocino Co., Tony Chess
coll., June 29, 1978 - 1 male.
Diagnosis. Male (8.7 mm): Body relative slender, coxal
plates shallow. Head, eye large, subrhomboidal. Antenna 1 ,
peduncular segment 3 medium; flagellum with ~45 short
segments; accessory flagellum, truncate apex with 2 longish
setae. Antenna 2, peduncular segment 5 not shorter than 4.;
flagellum with ~25 segments, thickest proximally, each with
distal ring of short “bottle-brush” setae.
Upper lip lobes distinctly asymmetrical. Lower lip,
inner lobes deep, outer lobes short-ovate. Mandible, molar
prominent, apex blunt; spine row with 8-10 thick, apically
acute blades; incisor, cutting edge with 6 uneven teeth; left
lacinia 8-dentate; palp segment 3 with 11-12 pectinate inner
marginal “D” spines. Maxilla 1, palp stout, with 6 apical
spines. Maxilla 2, outer plate not narrowing distally, apex
strongly setose. Maxilliped, inner plate with 10 apical facial
setae and 3 short apical spines; outer plate tall, distally
narrowing; palp, dactyl slender, nearly straight.
Coxae 1 & 2, hind margin with 1-2 median short spines;
coxa 4 shallow, broad. Gnathopod 1, carpus shorter than
deep, hind lobe narrow; propod ovate, palm very oblique,
gently convex, postero-distal angle with groups of 3 & 4
spines; dactyl strongly denticulate or serrated along proximal
2/3 of inner margin. Gnathopod 2, carpus short, hind lobe
smaller than in gnathopod 1 ; propod long-ovate, very oblique
palm merging smoothly with hind margin, not heavily
marginally setose; postero-distal angle with 2 groups of 4
spines; dactyl serrated behind.
Peraeopods 3 & 4, segments regularly spinose; segments
5 , hind margin with 5 clusters of short spines; dactyls short.
Peraeopods 5-7 closely homopodous, 5 slightly shortest;
bases broadly expanded, hind margin strongly convex,
minutely serrulate; segment 5 distinctly shorter than 4;
dactyls short.
Pleon plate 3, hind comer acuminate. Urosome 2 nearly
totally occluded dorsally by segment 1 & 3. Uropod 2, outer
ramus 2/3 length of inner ramus. Uropod 3, inner ramus with
5 serially paired marginal spines. Telson linguiform, relat-
ively narrow, length nearly twice width, apex sharply rounded.
Distribution. From southeastern Alaska to central
California (Dillon Beach), mostly under boulders, associated
with sessile invertebrates, Egregia, Corallina and other
algae, at LW level.
Etymology. From the Latin ^'serratus", with reference
to the serrated hind margins of the gnathopod dactyls.
Taxonomic commentary* Gnathopleustes serratus is
relatively primitive species in characters of the mouthparts
(maxilliped) and gnathopods (serrated dactyls), and near the
base of the genus phyletically.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
94
FIG. 21. Gnathopleustes serratusy new species. Male (8. 5 mm); female (10.0 mm). Graham I., B. C.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
Incisocalliope J. L. Barnard
95
Incisocalliope }. L. Barnard, 1959: 22.
Parapleustes Gurjanova,1951: 645 (part.).— Barnard &
Given, 1960: 42 (part.).— Guijanova, 1972; 131 (part.).—
Watling & Maurer, 1973: 1 (part).— Barnard & Karaman,
1991: 649 (part).— Ishimaru, 1994: 46 (part).
Parapleustes (derzhavini group) Ishimaru, 1984:407,450.
Type species. Incisocalliope newportensis Barnard, 1959,
original designation.
Species composition. Incisocalliope dilatatus (Ishi-
maru, 1984); /. bairdi (Boeck, 1871); /. derzhavini
(Gurjanova, 1938); I. nipponensis, new species; /. makiki (J.
L. Barnard, 1970); /. aestuarius (Watling & Maurer, 1973); I.
filiaris (Hirayama, 1988).
Diagnosis. Body small to medium, slender, smooth
above. Head, rostrum short, little exceeding rounded ante-
rior head lobe. Eye small, medium rounded to ovate. Antennal
flagella slender, nearly bare; antenna 1 longer than antenna
2. Antenna 1, peduncular segments 2 & 3 short, peduncle 1
lacking postero-distal cusp; accessory flagellum minute,
triangular.
Mouthparts modified. Upper lip, median notch deep,
lobes asymmetrical. Lower lip broad, squat, outer lobes
steeply oblique. Mandible, molar reduced to a small setulose
knob; left lacinia 9-12 dentate; blades numerous (9-14),
unmodified; incisors 8-dentate; palp segment 2 medially
sparsely setose, segment 3 longest, apically truncate, segment
1 medium. Maxilla 1, inner plate with 1 apical seta; outer
plate with 9 medium strong pectinate spine-teeth; palp not
broadened, surface setulose, apex rounded, with few spines,
segment 1 with lateral seta(e). Maxilla 2, inner plate little
broadened, inner margin with single large plumose seta.
Maxilliped, inner plate with few (2-4) “button” spines; seg-
ment 3 longer than palp segment 2; outer plate columnar,
palp segment 3 largest, segment 3 often with short inner
distal spine-teeth; dactyl slender.
Coxal plates 1 -4 medium deep; coxa 4 largest & strongly
excavate behind; coxa 1 shortest, slightly expanding distally ;
hind cusps small, single or double. Gnathopods 1 & 2,
variously (mainly strongly) subchelate, subequal, not sexually
dimorphic. Gnathopod 1, basis normal, anterior margin
often strongly setose; meral process weak; carpus short,
deep; propod, palm convex, with median tooth, not continuous
with weakly setose posterior margin; postero-distal angle
with 2-3 spine groups not extending onto palm.
Peraeopods of medium length and stoutness, segments
spinose but not setose; segment 4 slightly longer than and
distally overhanging segment 5; dactyls medium, curved.
Peraeopods 5-7 homopodous, increasing slightly posteriorly;
coxae medium deep, rounded behind; bases broad, hind
margin nearly flat.
Pleon segments normal, hind comers acuminate (but not
hooked), lower margins lightly spinose. Pleopods normal,
not sexually dimorphic, rami medium strong. Uropods 1 &
2 extending to or beyond uropod 3, rami spinose. Uropod 1 ,
inner ramus slightly the longer. Uropod 2, outer ramus
distinctly the shorter. Uropod 3, rami relatively short, inner
ramus distinctly the longer.
Telson medium long, keeled proximally below, apex
rounded, with small paired notch and seta.
Coxal gills undescribed. Brood plates large, broad.
Taxonomic remarks. Incisocalliope is phyletically the
most advanced genus, with closest relationships to Gnatho-
pleustes and, to some extent, to Trachypleustes. These
groups may be distinguished by a combination of character
trends, as outline in the key and Table I. (p. 128).
Distributional ecology. Species of Incisocalliope occur
mainly in temperate or subtropical regions of pan-Pacific
and North Atlantic regions, in shallow occasionally estuarine
habitats. By contrast, the slightly less phyletically advanced
members of Gnathopleustes are confined to open coast
habitats of the North American Pacific region, but some
(e.g., G. pachychaetus) exhibit brackish- water tolerance.
Incisocalliope newportensis Barnard
(Fig. 22)
Incisocalliope newportensis Barnard, 1959: 22, pi. 2.
Parapleustes pugettensis Barnard & Given, 1960: 43, fig.
4.— Barnard, 1969b: 178.— Barnard & Karaman, 1991: 650.
Material examined. J. L. Barnard's type specimen (Stn.
#9, AHF- # 522) has been made available for this study,
courtesy of the Los Angeles County Museum.
Diagnosis. Female (5.0 mm): Head, eyes medium, oval,
black. Antennae especially peduncles, stout. Antenna 1 the
longer; peduncular segment 1 large, 2 & 3 short; flagellum
long. Antenna 2, peduncular segment 5 > segment 4.
Mandible, spine row with 8-9 blades; left lacinia 8-9
dentate; palp segment 3 with 6-7 posterior marginal pectinate
D spines. Maxilla 1, palp segment 2, surface setulose,
segment 1 with single “shoulder” seta. Maxillas 2, inner
plate broad, short. Maxilliped, inner plate with button
spines.
Coxal plate 1 large, expanding distally, little shorter
than 2, with single postero-distal cusp. Coxa broad, width =
depth. Gnathopods strongly subchelate, propods medium
large; basis, anterior margin with a few scattered short setae;
hind margin with a few setae proximally. Gnathopod 2,
basis, anterior margin nearly bare.
Peraeopods 3 & 4, segment 5 short, length < segment 5;
Peraeopods 5-7, bases broad, convex behind; segment 5
short dactyls strong.
Pleon plate 3, hind comer acuminate, hind margin nearly
straight. Uropod l,peduncle,outermargin strongly spinose.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
96
KEY TO SPECIES OF INCISOCALUOPE
1. Coxa 1 distinctly shorter than coxa 2; gnathopod 1, basis, anterior margin strongly setose (20+
setae); peraeopods 3 & 4, basis, anterior margin lined with short setae throughout 2
—Coxa 1 about as deep as coxa 2; gnathopod 1, basis, anterior margin nearly bare or with fewer
than 15 setae; peraeopods 3 & 4 basis, anterior margin weakly setose
2. Uropod 2, rami subequal; peraeopod 7, basis medium broad, postero-distal lobe ordinary, not
reaching to segment 4; dactyls short, < 1/3 segment 6 L aestuarius (p. 104)
— Uropod 2, outer ramus distinctly (1/3) the shorter; peraeopod 7, basis narrow, hind lobe deep,
reaching segment 4 behind; dactyls heavy, strong, >1/3 segment 6 Lfilialis (p. 102)
3. Gnathopods 1 & 2, propods relatively weak, depth not greater than carpus; gnathopod 1, basis
with antero-distal cluster of 3 long setae
—Gnathopods 1 & 2, propods relatively stout, strong, depth greater than carpus; gnathopod 1, bas-
is antero-distally with 0-2, or 4, long setae 5.
4. Gnathopod 2, basis with 2 strong antero-distal setae; antenna 1, peduncular segment 1 large,
distinctly longer than segments 2 & 3 combined /• derzhavini (p. 102)
Gnathopod 2, basis lacking strong antero-distal setae; antenna 1, peduncle 1 ordinary, length
about equal to segments 2 & 3 combined nipponensis (p. 1(X))
5. Gnathopod 1, basis, anterior marginal setae long, length > width of basis; antenna 2, peduncular
segment 5 not longer than 4 makiki (p. 98)
Gnathopod 1, basis, anterior marginal setae short, length < width of basis; antenna 2, pedunc-
ular segment 5, length distinctly > segment 4 6.
6. Peraeopods 3 & 4, segment 5 regular, length ~ segment 4; antenna 2, peduncular segments 4 &
5 slender, length 3-4 X width (p. 96)
—Peraeopods 3 & 4, segment 5 short, thick, length < segment 4; antenna 2, peduncular segments
4 & 5 relatively short, thick, length "'2X width 7.
7. Peraeopod 4, coxa broad, width -depth; uropod 1, peduncular outer margin lined with 10-12
strong spines; uropod 3, inner ramus with 5-6 pairs of marginal spines . . I. newportensis (p. 95)
—Peraeopod 4, basis narrow, width < depth; uropod 1, peduncular margin proximally with cluster
of 3-4 Stout spines; uropod 3, inner ramus, margins with 3-4 pairs of spines. /. dilatatus (p. 97)
Uropod 2, outer ramus -3/4 inner ramus. Uropod 3, inner
ramus with 6 pairs of marginal spines. Telson long, apex
truncated.
Taxonomic and distributional commentary. The
type locality of Incisocalliope newportensis is Newport Bay ,
California. The species has been recorded authentically on
the eastern Pacific coast only south of Pt. Conception. 1 1
has been confused with Gnathopleustes pugettensis. How-
ever, morphological differences are major, and the latter is
also larger at maturity and more northerly in distribution.
Incisocalliope newportensis and/, bairdi (J. L. Barnard)
form a primitive species pair within the genus. Further
species of the genus may yet be discovered, especially in the
Baja and Gulf of California regions, and in the southern Sea
of Japan and China Sea regions. Differences noted here
between this pair and the remaining six species may eventually
form a basis for recognition of the two phyletic groups at the
subgeneric level (Fig. 43, p. 127).
Incisocalliope bairdi (Boeck)
(Fig. 23)
Paramphitoe bairdi Boeck, 1871: 45-46, 50, pi. 1, fig. 3. —
Barnard, 1956: 36, Plate 12. — Barnard & Karaman, 1991:
650.
Neopleustes bairdi Stebbing, 1906: 314-315.
non Parapleustes pugettensis Barnard & Given, 1960.
Diagnosis. Male (5.5 mm): Head, eyes medium large,
oval-round, black. Antenna 1 the longer, flagellum 36-
segmented. Antenna 2, peduncular segment 4 & 5 slender,
segment 5> 4.
Mandible, spine row with 1 5 blades; lacinia with 9 teeth;
palp segment 3 with 9-10 posterior marginal “D” spines.
Maxilla 1 , palp segment 2, apex with 7 spines and facial setal
row, segment 1 with 2 short “shoulder “ setae. Maxilla 2,
plates small, inner plate not broadened. Maxilliped, inner
plate with 4-5 apicEil marginal “button” spines outer plate
columnar; palp segment 3 large, heavy.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
97
FIG. 22. Incisocalliope newportensis (Barnard 1959). Female (5.0 mm). New port Bay, California.
Coxal 1 large, broadening distally, lower margin gently
convex, with single postero-distal cusp. Coxa 4 narrow,
width < depth. Gnathopods large, strongly subchelate.
Gnathopod 1, basis, anterior and posterior margins nearly
smooth; merus with short distal process ; propod, hind margin
straight, with single distal setal group. Gnathopod 2, hind
margin of coxa with 2-3 short spines; basis nearly bare of
setae.
Peraeopods 3 & 4, segment 5 not shortened, length ~=
segment 4. Peraeopods 5-7, bases medium broad, hind
margins nearly straight; segment 5 not shortened. Dactyls
medium.
Pleon 3, hind comer acuminate, Uropod 1, peduncular
outer margin with 7-8 spines, outer ramus very slightly the
shorter. Uropod 2, outer ramus about 3/4 length of inner r am -
us. Uropod 3, inner ramus with 5 pairs of marginal spines.
Telson medium, narrowing to smoothly rounded apex.
Taxonomic commentary. The species was first
described by Boeck (1872) from southern California, and
rediscovered in fresh material from the same region by J. L.
Barnard (1956). Barnard's description and figures, more
detailed than the accounts of Boeck (loc. cit.) and Stebbing
“(1906) form the basis of the present analysis.
Incisocalliope dilatatus (Ishimam)
(Fig. 24)
Parapleustes dilatatus Ishimam, 1984: 425, figs. 17-20.—
Barnard & Karaman, 1991: 650.-Ishimam, 1994: 54.
Diagnosis. Male (4.7 mm): Head, eye medium large
almond-shaped, black. Antennae relatively short, first slightly
the longer. Antenna 1, peduncular segment 1 short, thick;
flagellum 27-segmented. Antenna 2, peduncular segments 4
& 5 relatively long, slender, 5 > 4; flagellum 1 8-segmented.
Mandible, spine row with 10 blades; left lacinia 9-
dentate; palp segment 3 with 6 posterior marginal “D”
spines. Maxilla l,palp segment 1 with 2 "shoulder” setae;
segment 2, apex oblique, with 4 spines and numerous facial
AMPHIPACmCA VOL II NO. 1. AUG. 31, 1995
98
FIG. 23. Incisocalliope bairdi (Boeck, 1971). Male (5.5 mm). S. California, (after Barnard, 1956).
setae. Maxilla 2, inner plate very slightly broadened.
Maxilliped, inner plate with 3 apical “button” spines; outer
pate, with 2 slender apical spines; palp segment 3 with distal
inner facial scales .
Coxal plate 1 large, distal margin convex, hind comer
with 2 small cusps, posterior margin with 2 short spines.
Coxa 4 medium, depth > width. Gnathopods strongly
subchelate, propods relatively large. Gnathopod 1, basis
with 1-2 stout anterior marginal setae, hind margin nearly
bare; mems lacking postero-distal process; propod with
superior medial facial cluster of setae; hind margin with
single distal setal group. Gnathopod 2, anterior and posterior
margins with weak, short setae; merus with strong postero-
distal process.
Peraeopod 3 & 4, segment 4 short, length > segment 5,
dactyl medium. Peraeopods 5-7, bases broad, rounded
behind; segment 5 short, length < segment 4.
Pleon plate 3, hind corner acuminate. Uropod 1,
peduncular outer margin relatively weakly spinose, with
cluster of 3 strongest spines proximally; rami weakly
marginally spinose; outer ramus distinctly the shorter. Uropod
2, peduncle with 2 strong outer marginal spines. Uropod 3,
rami short, inner ramus with 3-4 marginal spines. Telson
relatively short narrowly slightly to broadly rounded apex.
Female (6.0 mm). No discernible difference from the male
Taxonomic commentary. Incisocalliope dilatatus is
morphologically closest to /. makiki Barnard from the
Hawaiian Islands (Fig. 44, p. 129). Both are members of
the advanced subgroup that includes, /. derzhavini and I.
filialis of the western Pacific region.
Distribution. Japan Sea, southern shores of Hokkaido,
under marine algae, LW level. Females ov. , May to August.
Incisocalliope makiki (J. L. Barnard)
(Fig. 25)
Parapleustes derzhavini makiki Barnard, 1970: 227.
Diagnosis. Female (4.2 mm): Head, eye medium large,
reddish or dark brownish, irregularly roundish. Antenna 1 ,
peduncular segment 1 large > 2 & 3 combined, flagellum 24+
segmented. Antenna 2, peduncular segment 4 & 5 medium
stout, subequal, flagellum 18+ segmented.
Mandible, spine row with 8 blades, left lacinia 10-11-
AMPHIPACIFICA VOLH NO. 1. AUG. 31, 1995
99
VIG.HX. IndsocamopedUatatus (Ishimaru, 1984). Male (4. 7 mm). Hokkaido, (after Ishimaru, 1984).
dentate; palp segment 3, inner margin with 7 pectinate “D”
setae. Maxilla 1, inner plate small, with 1 apical seta,
Maxilliped, inner plate with 2 apical “button spines; outer
plate with 2 slender apical spines; palp segment 3, with
pectinations or scales at base of dactyl.
Coxa 1 medium large, lower margin convex, hind comer
with 1-2 cusps, hind margin with single spine. Coxa 2 with
1 postero-distal cusp. Coxa 4 broad, as wide as deep.
Gnathopods strongly subchelate; propod of gnathopod 2
l3rger than 1. Gnathopod 1, basis, anterior margin with
numerous (~10) strong setae, each longer than width of basis,
hind margin weakly setose proximally ?; mems lacking distal
process 1; propod with superior facial group of 2 setae;
posterior margin bare. Gnathopod 2, basis virtually lacking
marginal setae; merus with postero-distal process; propods,
hind margin with distal group of spines and setae.
Peraeopods 3 & 4, basis, margins weakly short-setose;
segment 5 slightly shorter than 4; segment 6, hind margin
spinose. Peraeopods 5-7, basis moderately broad, hind
margins convex, lower hind lobe shallow, not reaching
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
100
FIG. 25. Incisocalliope makiki (J. L. Barnard). Female (4.2 mm). Hawaii (after Barnard, 1970).
segment 4; segment 5 shorter than segment 4.
Pleon 3, hind comer minutely acuminate. Uropods 1 &
2 strong. Uropod 1 , peduncle, outer margin strongly spinose;
outer ramus distincdy the shorter. Uropod 3, inner ramus
slender, margins with 6 spines. Telson short, broad, little
longer than wide, normally rounding apically.
Distribution. Oahu, Hawaiian Islands; 3-4 m in depth.
Taxonomic commentary. Incisocalliope makiki merits
full species status here. Its presumed common ancestor with
I. dilatatus may have penetrated the Hawaiian archipelgo in
the early Tertiary Period (p. 130).
Incisocalliope nipponensisy new species
(Fig. 26)
Parapleustes denhavini Ishimaru, 1984: 417.-Ishimaru,
1994: 54 (part.)
Diagnosis. Female (5.0mm); Head, eye small, rounded,
black. Antenna 1, peduncular segments 1-3 short, segment
1 = 2 and 3 combined; flagellum, slender 25-segmented.
Antenna 2, peduncular segment 4 shorter than 5, medium
thick; flagellum slender, 24-segmented.
Mandible, spine row with 8 blades; left lacinia 11-
dentate; palp segment 3 with 7 posterior marginal “D” setae.
AMPHIPACIFICA VOLH no. 1. AUG. 31, 1995
101
FIG. 26. Incisocattiope nipponensis , new speci es. Female (4.6 mm). Japan Sea. (after Ishimaru, 1984).
Maxilla 1, palp segment 1 with single “shoulder” seta;
segment 2 apically with 4 spines and facial row of 3 setae.
Maxilla 2, inner plate short, not broadened. Maxilliped,
inner plate with 3 “button” spines; outer plate with 2 apical
slender spines; palp segment 3 with distal inner marginal
pectinations.
Coxa 1 small, 1/3 shorter than 2, with single postero-
dts^ cusp and 1 -2 posterior marginal short spines. Coxa 4 Type material Female “a” /5 n mmt c.
Pleon plate 3, hind comer strongly acuminate. Uropod
1, peduncle, outer margin strongly spinose, Uropod 2, inner
ramus longer than peduncles, 1/3 longer than outer ramus.
Uropod 3, inner ramus 1/3 longer than outer ramus, with 4-
5 pairs of marginal spines. Telson medium long, narrowing
to sharply rounded apex.
weakly subchelate, propods only slightly broadened.
Gnathopod 1, basis with 15+ long anterior marginal setae
and ~ 10 short postero proximal marginal setae, merus with
distal cusp; propod, hind margin with single distal spine.
Gnathopod 2, basis, margins nearly bare merus with acute
postero-distal cusp.
Peraeopods 3 & 4, regular, segment 5 not noticeably
shortened, dactyls medium. Peraeopods 5-7, base broadly
expanded, hind margins convex, dactyls stout.
2 females. Paratypes, at stations 2-4 along south coast of
Hokkaido, 0.5 m depth, among algae. Collections of the
Zoological Museum, Faculty of Science, Hokkaido
University.
Distribution. Shores of Hokkaido, LW to 5 m depth
Sargassum belt, Laminaria belt; among Leathesia and other
algae scraped from surface of boulders.
AMPHIPACIFICA VOLH NO. 1. AUG. 31, 1995
102
FIG. 27. Incisocalliope derzhavini (Gurj., 1938). Female (4.0 mm). Japan Sea. (after Gurjanova, 1951).
Taxonomic commentary. This description is based on
the careful work of Ishimaru (1984). He had previously
found it very similar to the female (4.0 mm) of Neopleustes
derzhavini from the sea of Japan, described by Guijanova
(1951), that is treated below (see also Fig. 27).
Incisocalliope derzhavini Gurjanova
(Fig. 27)
Neopleustes derzhavini Gurjanova, 1938: 317, fig. 31.
Gurjanova, 1951: 645, fig. 442.
Parapleustes derzhavini Barnard & Karaman, 1991: 650
(part)
Diagnosis. Female (4.0 mm): Head, eyes medium,
round, black. Antenna 1, peduncle 1 large, length > seg-
ments 2 & 3 combined; flagellum medium long, slender, 25-
27 segmented. Antenna 2, peduncular segment 4 & 5 short,
thick, 5 > 4; flagellum 18- segmented.
Mandible, spine row with 6-8 blades; palp segment 3
with 5-6 pectinate “D” spines. Maxilla 1, palp segment 1
with 1 shoulder seta; segment 2, rounded apex with 4 spines.
Maxilla 2, inner plate not broadened. Maxilliped, inner plate
with 3 (?) button spines, palp segment 3 with pectinations at
base of dactyl?
Coxa 1 relatively short, little broadening distally, lower
margin convex, with 1 hind cusp. Gnathopods relatively
weakly subchelate; propods not deeper than respective carpus.
Gnathopod 1, basis, anterior margin with 9-10 stout setae,
concentrated distally, mostly longer than width of basis;
merus lacking distal process; propod hind margin bare.
Gnathopod 2, basis, antero-distal margin with 2 very large
stout setae, hind margin nearly bare; merus with short distal
process?, propod, hind margin with single distal seta.
Peraeopods 3 & 4 ordinary. Peraeopods 5-7 ordinary;
bases moderately expanded, ovate.
Pleon plate 3, hind corner acuminate, lower margin
gently convex, with 4-5 small spines. Uropod 3, inner ramus
slender, margins each with 4 spines. Telson medium long,
narrow, sharply rounding at apex.
Distributional ecology. Japan Sea; tidal zone.
Taxonomic commentary. Gurjanova's original figures
and description are limited but sufficiently detailed to separate
/. derzhavini from the material of Ishimaru (loc. cit.) des-
cribed above as /. nipponensis, new species.
Incisocalliope fHiaUs (Hirayama)
(Fig. 28)
Parapleustes filialis Hirayama, 1988; 40, figs. 265-268. —
Barnard & Karaman, 1991: 650. — Ishimaru, 1994: 54.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
103
FIG. 28. Incisocalliope filialiss (Hirayama). Male (3,
Diagnosis. Male (3.5 mm): Body small, pleonites slightly
raised postero-dorsally. Head, eyes medium large, nearly
round, black. Antennae slender, medium long. Antenna 1,
peduncular segment 2 short, - 1/2 segment 1 ; flagellum - 1 5-
segmented. Antenna 2, peduncular segments 4 & 5 stout, 5
slightly the longer; flagellum 16-segmented.
Upper lip with relatively deep V-notch, lobes
asymmetrical. Lower lip inner lobes broad, outer lobes
oblique. Mandible, molar process small, vestigial; spine row
with 6 short blades; incisor (left) with 4 proximal large teeth
and 4-5 distal denticles; palp segment 3, basal “A” seta small,
inner margin with 5-6 pectinate “D” spines; left lacinia 10-
dentate. Maxilla 1, inner plate with single apical seta; palp
segment 1 with single “shoulder” seta; distal segment, apex
with 4-5 slender spines. Maxilla 2, inner plate short, not
broadened, inner margin with single proximal plumose seta.
Maxilliped, innerplate medium, inner margin notched distally,
apex with 5 slender spines; outer plate slender, truncate apex
with 2 slender spines; palp stout, segment 3 with distal
5 mm). Ariake Sea, Japan, (after H irayama, 1988).
pectinate denticles at base of dactyl; dactyl slender, straight,
length about equal to segment 3.
Coxal plates 1-3 lower margins broadly rounded, hind
margins with 1 -2 median short spines, hind comers each with
single cusp. Coxa 1 distinctly shorter than 2. Gnathopod 1,
anterior margin of basis strongly setose, (20+ setae), some
setae longer than width of basis; hind margin of basis
proximally with 6-8 shorter setae.; carpus short, as deep as
long, hind lobe stout; propod short, expanding distally, inner
face with scattered setae; palmar margin convex, oblique
slightly longer than hind margin, postero-distal angle with
spine groups on either side of short dactyl-tip depression,
distal spines larger; dactyl slender, with small distal unguis.
Gnathopod 2, anterior margin of basis weakly setose, with
single distal seta; hind margin proximally with row of setae;
carpus short, hind lobe narrow propod subovate, longer and
more slender than in gnathopod 1 ; two groups of longer and
stronger spines at palmar angle.
Peraeopods 3 & 4 relatively short and stout; bases.
AMPHIPACIFICA VOL II NO. I. AUG. 31, 1995 104
FIG. 29. Incisocalliope aestuarius (Watting & Maurer, 1973). Female (4. 0 mm). Delaware Bay.
anterior and posterior margins moderately strongly setose;
segment 5 shorter than 4; segment 6, hind margin with 3
groups of stout spines; dactyl heavy, medium. Peraeopods
5-7, bases only moderately broadened, least in peraeopod 7,
postero-distal lobes large, deep, reaching segment 4; segment
5 shorter than 4; dactyls stout.
Pleon plate 3, lower margin weakly spinose, hind corner
squared, not acuminate. Pleopod peduncles, outer margin
strongly setose. Uropods 1 & 2 large, extending well beyond
uropod 3. Uropod 1, peduncle large, outer margin finely
spinose. Uropod 2, outer ramus distinctly the shorter. Uro-
pod 3, outer ramus long, length -2/3 long inner ramus, with
6 pairs marginal spines. Telson oblong, apex subacute.
Distribution. Ariake Sea, Japan; sublittoral.
Taxonomic commentary. Hirayama likened Inch-
calliope filialis to Incisocalliope derzJtavini but found sev-
eral species differences. The species is an atypical Para-
pleustes, with several features more reminiscent of Gnatho-
pleustes. These include the unlike gnathopod propods,
narrow peraeopod bases; and in mouthparts, the broad lower
lips, "shoulder" seta on palp of maxilla 1, etc. The species is
close to /. dilatatus in the armature of the maxilliped palp.
Incisocalliope aestuarius (Watling & Mauer)
(Fig. 29)
Parapleustes aestuarius Watling & Mauer, 1973: 252, figs.
1-4. — Fox & Bynum, 1975: 230. — Ishimaru, 1984: 431. —
Barnard & Karaman, 1991: 650.
Diagnosis. Female (4.0 mm): Head, eye small round,
black. Antenna 1, peduncular segment 1 large, stout, length
about equal to segments 2 & 3 combined. Flagellum long,
-40 segments. Antenna 2, peduncular segments 4 & 5 short,
medium, segment 5> 4; flagellum ! 25-segmented.
Mandible, spine row with ~14 slender blades, distally
largest; left lacinia 10-dentate; palp segment 3 with 8-9
slender pectinate “D” spines. Maxilla 1, segment 1 with
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
105
single shoulder seta; segment 2 , with numerous short facial
seme, rounded apex with 4 spines; outer plate, inner apical
spine elongate. Maxilla 2, inner plate not broadened.
Maxilliped, inner plate with 2-3 apical marginal “button”
spines; outer plate with 4 apical slender spines; palp segment
3 distally with pectinations at base of dactyl.
Coxal plate 1 short, lower margin convex, hind comer
with 2-3 cusps posterior margin with 2-3 stout spines. Coxa
4 little broadened deeper than wide. Coxa 5 deep. Gnathopods
relatively weakly subchelate; basis, anterior margin lined
with numerous (20+) setae some longer the width of basis,
hind margin strongly lined with shorter setae; mems lacking
distal cusp; propod relatively short, not deeper than carpus;
with superior and inferior facial clusters of small setae; hind
margin shorter than palm, with single distal setal group.
Gnathopod 2, basis distal with short setae, hind margin
distally with several setal groups; merus with short posterior
tooth; propod, hind margin with 2 distal setal groups.
Peraeopods 3 & 4 basis, anterior margin strongly short-
setose; segment 5 shorter than 4; dactyls relatively short.
Peraeopods 5-7, bases moderately broadened, hind margins
convex; segment 5 slightly shorter than 4.
Pleon plate 3, hind comer acuminate, slightly produced.
Uropods 1 & 2 strong, rami longer than peduncle. Uropod
1, peduncle, outer margin strongly spinose; rami subequal.
Uropod 2 outer ramus little shorter than inner, margins
strongly spinose. Uropod 3 rami long, slender, inner ramus
with 7 pairs of margins spines. Telson medium long, apex
rounded.
Distributional ecology: From Delaware Bay,
Chesapeake Bay to Albemarle Sound and estuaries of the
southeastern states, on wharf pilings, among bryozoans,
hydroids, and other sessile invertebrates.
Taxonomic & distributional commentary. The
original description (as Parapleustes aestuarius) is limited
in a number of features, some of which were pointed out by
Fox & Bynum (loc. cit.). The species is remarkably close
morphologically to Incisocalliope filialis from the Sea of
Japan. The relationship appears closely phyletic, but the
disjunct distribution of the two forms defies explanation that
is entirely satisfactory (see p. 130).
Trachypleustes, new genus
Type species. Trachypleustes vancouverensisy new species.
Species composition. Trachypleustes trevori, new
species (and varieties: Pribilof Islands, San Juan Batista I).
Diagnosis. A group of small, smooth-bodied pleustids
having short antenna 1 peduncular segments, unequal
gnathopods, slender legs, slender unequal rami of uropods,
and heavily chitinized, “molanzed”, or otherwise strongly
modified mandibular blades.
Body smooth above, slender. Head small; rostrum
slightly produced beyond subacute head lobe. Eyes large.
Antennae slender, elongate. Antenna 1, peduncle 1 large,
without postero-distal process; segment 2 medium short;
accessoiy flagellum minute, triangular, with a few apical
setae. Antenna 2, peduncular segments 4 & 5 subequal,
setose; flagellum elongate.
Mouthparts strongly modified. Upper lip moderately
incised and asymmetrical. Lower lip broad, squat, outer
lobes oblique. Mandible, molar minute; spine row with few
(4-6), strongly thicked and/or flattened blades; left lacinia
irregularly 10-11 dentate; incisor multidentate; palp, segment
3 longest, medial pectinate setae numerous ( 12+); segment 2
sparsely setose medially. Maxilla 1, outer plate short, spines
tall; palp long, apex with slender spines and setae, segment
1 lacking lateral setae; inner plate 1-setose. Maxilla 2, inner
plate medium broad, with 1 large inner plumose seta;
maxilliped, palp and dactyl strong; inner plate short, apex
sloping, with 3-5 button-teeth and 4-6 inner marginal setae;
outer plate narrow, apex and inner margin slender-spinose.
Coxal plates 1-4 increasing in size posteriorly; coxa 1
small, not expanded distally; coxa 2-4 deeper than body
plates; lower margins nearly straight, with hind cusp.
Gnathopods 1 & 2 weakly subchelate, similar in form but
unequal in size, not sexually dimorphic; gnathopod 2 distinctly
the larger. Gnathopod 1, basis weakly setose anteriorly;
carpus shallow, more than half length of propod; length of
palm oblique, with small median tooth; length about equal to
smooth hind margin; postero-distal angle with 2 groups of
spines; dactyl slender. Gnathopod 2, carpus shorter, hind
lobe deeper, anterior margin about half length of propod; 2-
3 spine groups at posterior angle.
Peraeopods 3-7 slender, dactyls normally developed.
Peraeopods 5-7 normally homopodous; bases regularly broad
and rounded behind; segment 4 (merus) postero-distal process
strongly overhanging segment 5.
Pleon plates 1-3 regular; lower margins spinose, hind
comers variously acuminate. Pleopods strong, not sexually
dimorphic.
Urosome 2 not occluded dorsally. Uropods 1 & 2
slender, marginally strongly spinose; rami unequal, inner
ramus longer than peduncle. Uropod 3, rami markedly
unequal, strongly spinose. Telson medium, apex rounded;
penicillate setae slightly proximal to mid point.
Coxal gills small to medium, saclike, largest on
peraeopods 4 & 5.
Distributional commentary. Members of the genus
are known only from northern parts of the North American
Pacific coastal marine region, in association with sponges
and large sessile invertebrates.
Etymology. A combining form of the Greek root
''trachytes'^ roughness, and the generic name Pleustes, that
alludes to the rough, molarlike appearance of the mandibular
blades
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
106
Taxonomic Commentary. This generic group is
distinguished by the heavily molarized and pavementlike
mandibular blades, the unequal, non sexually dimorphic
gnathopods, slender peraeopods, and the elongate, spinose
uropod rami. Phyletically the genus Trachypleustes appears
closest to Gnathopleustes, but more distant from Inciso-
calliope.
Trachypleustes vancouverensis, new species
(Fig. 30)
Material examined.
eBRITISH COLUMBIA.
Northern Vancouver 1. : ELB Stn 0 1 , Cape Scott, Experiment
Bight, under boulders, among algae, LW level, July 18,
1959. - female ov. (4.5 mm), Holotype (slide mount), CMN
Cat. no. NMCC 1995-0086.
Diagnosis. Female ov. (4.5 mm): Head, rostrum pro-
longed beyond lateral head lobe; eye subquadrate. Antenna
1, peduncular segment 1 long, extending to midpoint of
peduncular segment 4 of antenna 2; flagellum ~'28-segmented.
Antenna 2, length about equal to antenna 1 ; flagellum -28-
segmented.
Lower lip, inner lobes very broad, shallow. Mandible,
molar process prominent, apex blunt; spine row distally with
4 thick short blades having rough, conical apices, and
proximally with several short vestigial blades; cutting edge
of incisor with 7-8 unequal teeth; palp segment 3 apex blunt,
inner distal margin with 1 2 slender pectinate “D” spines; left
lacinia large, broad, cutting edge with 10 small uneven teeth.
Maxilla 1, palp slightly narrowing distally, rounded apex
with 6 slender spines. Maxilla 2 outer plate narrow. Max-
illiped, inner plate short, with 3 inner marginal plumose
setae, and 4 apical button spines; outer plate slender, nar-
rowly subtruncate, with 2 very slender spines; palp ordinary.
Coxae relatively deep, broad, hind comers with single
small cusp. Gnathopod 1, propod about half size of propod
of gnathopod 2; palmar margin smoothly continuous with
posterior margin; proximal spine group at postero-distal
angle with single spine and split-tipped seta; posterior
margin distally with single spine and setae. Gnathopod 2,
carpal lobe, some distal setae pectinate; propod stout,
subovate; proximal spine group at postero-distal angle with
5 spines and split-tipped seta; posterior margin distally with
small cluster of split-tipped setae.
Peraeopods 3 & 4 ordinary, slender; segment 4, anterior
margin with 3-5 tufts of slender spines; dactyls strong.
Peraeopods 5-7 closely homopodous; bases broad, hind
margins smoothly convex; margins of segments 4-6 with
cluster of short spines; segment 5 slightly shorter than 4;
dactyls strong, curved.
Pleon plates 1-3, hind comers acuminate. Urosome 2
with free dorsal margin. Uropod 3, outer ramus relatively
long, -60% of inner ramus.
Telson distally with several dorsal setules; apex unevenly
rounded. Coxal gills on peraeopods 4-6 relatively large,
broadly saclike.
Etymology. The name alludes to the type locality on
Vancouver Island, British Columbia.
Distributional ecology. The species has been confirmed
only for the type locality. Northern Vancouver Island, from
under rock and algal habitats at LW level
Taxonomic commentary. The species name vancouv-
erensis alludes to its known distribution on Vancouver Is-
land, British Columbia.
Trachypleustes trevori, new species
(Figs. 31, 32, 33)
Material examined. About 130 specimens taken at 23 loc-
alities, as follows:
ALASKA.
Pribilof Islands: D. B. Quayle coll., Nov. 23, 1965 - 1 female
ov (slide mount).
Southeastern Alaska. ELB Stns,. 1961: A168, Klokachef I -
1 female; A175 , San Juan Batista L, under rock, among
algae, LW level, July 26, 1961 - 1 female ov. (slide mount).
BRITISH COLUMBIA.
Queen Charlotte Islands; ELB Stn. E14a, Onward Pt.
Moresby I. July 13, 1957 - 1 ov. female (slide mount), 2 other
specimens.
Northcentral coast. ELB Stns., July, 1964: H7, McCauley I.
- 1 female ov; H65, Christie Pass - 2 females ov (slide
mounts), 1 im. ELB , 1959, Stn. N22, off Banks 1. - 1 male
(slide mount), 1 female, 28 other specimens.
Northern Vancouver L: ELB Stns., July, 1959: V5, Lemon
Pt., Nigei I. - 1 female ov (Slide mount); 03, Grant Bay - 5
females ov (2 slide mounts).
Southern Vancouver I.: ELB Stns., July 1970: P702 , Long
Beach, south end, from algae and sessile invertebrates,
under boulders, at LW level July 6-1 female; P719,
Botanical Beach, from kelp and sponges, under boulders at
LW level, Aug. 1-1 female ov.
ELB Stns., 1975: P2, Bamfield Marine Laboratory, from
floating log fouling community at surface, July 23-1 male,
1 female, 2 im.; P5c, Taylor I., Trevor channel, from
ascidians and sponges, under large boulder, July 25-2 males,
2 females.
ELB Stns., 1976 : B4, Off Brady’s Beach, naturalist's dredge,
60-70 m, sand & algae June 25-1 female; B7, Wouwer I.,
Broken L, from algae and sponges on bedrock walls at LW,
June 27 - 1 male, 1 female; B1 lb, Wickininnish Bay, south
end, LW sandy mud, June 29-2 females; B28, Edward King
L, among algae, under boulders, LW, July 10-1 female.
ELB Stns., 1977: B13, Trevor Channel, off Brady’s Beach,
6- 14m naturalist’s dredge, sand, stone, algae. May 25, 1977
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
107
FIG. 30. Trachypleustes vancouverensis, n. sp. Female ov (4.5 mm). Cape Scott, Vancouver Island.
^ Vancouver I.. LW level,Anita Voss coll., April
NMCC1995-0084; 2 females, Paratypes, CMN Cat. No. 25, 1986 - 1 male (slide mount) + -40 other specimens
NMCC1995-0085. B21b, Off Brady’s beach, 10-20 m O + 4U omer specimens.
naturalist’s dredge, algae, debris over sand, June 1 - 3 fe- WASHINGTON-OREGON
ofFnl'n ■ w ^ ^ ^August, 1966: W40,
OffEdw^d King I., from sponge, W.C. Austin Stn. 101/76 Mukkaw Bay at Sooes Pt. - 2 females, 12 male (slide
- 1 male (slide mount), 2 females. mounts); W58, Seal Rock - 1 male (slide mount).
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
108
FIG. 31. Trachypleustes trevori, new species,
Diagnosis. Female ov. (5.0 mm): Head, rostrum short,
little exceeding lateral process; eye nearly round. Antenna
1 much longer than antenna 2; peduncular segment 1 not
exceptionally large, length slightly longer than segments 2 &
3 combined; flagellum with ~42 segments, alternately with
aesthetascs. Antenna 2, peduncular segments 4 & 5 relatively
short, slender; flagellum with ~38 short segments, each with
whorl of short setae.
Female ov (5.0 mm). Trevor Channel, B. C.
Lower lip, inner lobes relative narrow and deep.
Mandible, molar minute much smaller than blades; spine
row with 4-5 very short, thick, flat, pavementlike blades;
cutting edge of incisor with 9-10 uneven teeth, smallest
distally; palp segment 3 narrowing gradually, inner margin
with 12 slender pectinate “D” spines; left lacinia broad, deep,
cutting edge with 10 uneven teeth. Maxilla 1 palp cylindrical,
obliquely rounded apex with 7 slender spines. Maxilla 2,
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
109
FIG. 32. Trachypleustes trevori, new species, A.-D locations; variations in mandibular blades & palp.
outer plate regular. Maxilliped, inner plate with 6 inner
marginal setae and 4 apical marginal “button” spines; outer
plate, apex narrowly rounding, with singly slender spine;
palp ordinary.
Coxae 1-3 medium, relatively shallow, hind comers
each with single small cusp. Gnathopod 1, propod much
smaller than propod of gnathopod 2; proximal spine group at
postero-distal angle with 2 spines; hind margin smooth,
lacking spines or setae. Gnathopod 2, carpal lobe lacking
pectinate setae; propod with proximal group of four spines at
postero-distal angle; hind margin with distal cluster of short
simple setae.
Peraeopods 3 & 4 ordinary, slender; segment 4, anterior
margin weakly setose; dactyls medium. Peraeopods 5-7,
bases not exceptionally broad, increasing posteriorly;
segments 4-6, margins with clusters of short spines; segment
5 not shorter than 4; dactyls medium, curved.
Pleon plates 1 & 2, hind comers acuminate; pleon plate
3, hind comer squarish. Urosome 2, dorsal margin nearly
occluded by segments 1 & 3. Uropods 1 & 2 long, slender,
margins of rami strongly serially spinose. Uropod 3, outer
ramus short, length -1/2 slender inner ramus having 7-8
pairs of marginal spines.
AMPHIPACIFICA VOLE NO. 1. AUG. 31, 1995
110
A
Pribilof i.
Female (4,0 mm)
B
Experiment Cove
Female (4.5 mm)
off Brady's beach
Female (5.0 mm)
off Brady's Beach
Female (5.0 mm)
FIG. 33. Trachypleustes trevori, new species. A-E locations. Variations in mandibular blades & palp.
Telson ordinary, apex smoothly rounded. Coxal gills on
peraeopods 4-5 short, saclike
Etymology. The species name alludes to the type locality
in Trevor Channel, Vancouver Island, British Columbia.
Distributional ecology. The species ranges from
southeastern Alaska, commonly throughout British Columbia
to central Oregon, along exposed rocky coasts, associated
with sponges and tunicate in under-rock habitats at LW level .
Taxonomic commentary. Material from the following
stations are presently considered variants ofT. trevori . This
treatment is not entirely satisfactory, since "variants" may
prove to be specifically distinct when more extensive material
can be studied:
Trachypleustes (small-eyed variety, Fig. 32D) having only
3-4 “pavement blades”, at Stns. A175; H14a: W40; W58.
Trachypleustes (northern variety, Fig. 33 A) having 5-6
thick, acute blades, palp with 6-7 pectinate spines, from the
Pribilof Islands, Bering Sea.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
Micropleustes, new genus
111
Parapleustes Barnard, 1969a: 425 (partim). — Ishimam, 1984:
432 (partim). — Barnard & Karaman, 1991: 649 (part).
Type species. Parapleustes nautilus J. L. Barnard 1969b:
199.
Species composition. Micropleustes behningi (Ishi-
maru, 1984); M. behningioides, new species; M. longimanus
(Ishimam, 1984); M nautiloides, new species.
Diagnosis. Body small, smooth to slightly mgose above.
Head, rostmm very short; head lobe subacute; inferior antennal
sinus elongate, shallow. Eyes small, roundish. Antennae
short, subequal, flagellaUttlelonger than respective peduncles,
weakly setose; accessory flagellum minute. Antenna 1 shghtly
the longer in male.
Mouthparts somewhat modified. Upper lip shallowly
and submedially notched, lobes slightly asymmetrical. Lower
lip wide, inner lobes deep, outer lobes oblique, rounded.
Mandible: incisor with few (6-8) teeth; left lacinia 6-9
cuspate; blades medium heavy, distally pectinate, 7-9 in
number; molar small, apex blunt, weakly setulose; palp seg-
ments relatively short, stout; segment 2 with few (3-8) inner
marginal setae; segment 3 subequal with few (5-10) inner
marginal pectinate setae. Maxilla 1, outer plate with 9 tall
apical spine-teeth; inner plate with single apical setae,
occasionally lacking; palp segment 2 normal, apex with 4
short spines, segment 1 with 1+ outer marginal setae. Maxilla
2, inner lobe slightly broadened, inner margin often with 2
plumose setae. Maxilliped, segment 3 not conspicuously en-
larged, longer than palp segment 1; dactyl strong, palp
segment 3 lacking distal process; inner plate with 1-2 stout,
apically pectinate inner marginal setae.
Coxal plates large, broad, deep; coxa 1 not broadened
or bent forward distally; postero-distal notch minute, often
multiple (2-4). Gnathopods small to medium strong, not
sexually dimorphic; propod tending to elongation; carpus
variable, hind lobe short or lacking; palm of propod shorter
than posterior margin, smoothly convex, lacking median
tooth, postero-distal angle with 1-2 groups of spines.
Peraeopods 3-7 short, medium stout, normally spinose;
segment 5 distinctly shorter than 4; dactyls normal, strong.
Peraeopods 5-7 regularly homopodous, bases very broad.
Pleon side plates deep, medium broad, hind comers little
produced. Pleopods normal, not sexually dimorphic, rami
subequal, slightly longer than peduncles. Urosome short,
segment 2 nearly occluded dorsally. Uropods short; rami of
uropod 1 and uropod 2 subequal, outer slightly the shorter,
sparsely spinose, about equal in length to peduncle. Uropod
3 short, extending less than twice length of telson; outer
ramus distinctly the shorter.
Telson elongate, dorso-lateral penicillate setae mark-
edly distal. Coxal gills of two types: anterior two pairs
slender, sublinear; posterior three pairs larger, platelike,
smallest on peraeopod 6.
Etymology. A combining form of the Greek “mikros “
(small) and the root generic name “pleustes”, referring to the
small body size of component members of the genus.
Distributional ecology. All five species of the genus are
endemic to the North Pacific region, three on the Asiatic, and
two on the North American coast.
Taxonomic commentary. Within subfamily Parapleust-
inae, the genus Micropleustes occupies a somewhat isolated
position. It combines a number of relatively plesio-morphic
character states, especially in the mouthparts, with arelati vely
advanced condition of the antennae, coxal plates, gills,
uropods, and telson. In balance, however, the genus is least
distant from the type genus Parapleustes (p. 127).
Micropleustes nautilus (J. L. Barnard)
(Fig. 34)
Parapleustes nautilus J. L. Barnard, 1969b: 199, fig. 55. —
Austin, 1985: 592.— Staude, 1987: 379, fig. 18.77.— Barnard
& Karaman, 1991: 650.
Material examined. About 185 specimens in 44 lots:
ALASKA.
Bering Sea: Attu I., Massacre Bay, C. E. O’Clair coll, June
23, 1972 - 2 females.
Amchitka I., Banjo Pt., Sta. BlGl, C. E. O’Clair coll. Aug.
14, 1971 - 32 specimens incl. males, females, im. (male,
female slide mounts); Ibid.. Stn. IA-2, plot 28, bedrock reefs
uplifted by underground nuclear tests. May 22, 1974 - 2
females.
Southeastern Alaska. ELB Stn. S5B7, 1980 - 1 female.
BRITISH COLUMBIA.
Queen Charlotte Islands. ELB Stns., June- July, 1957: W4a
(1);W12(1); W9a(l);H14(l).
Northcentralcoast. ELB Stns., July, 1964, 1959: H1(4);H33
(8); H39 (2); H44 (-20); H47 (1); N1 (1).
Vancouver I., north end. ELB Stns, July, 1959: 01 (4); 05
(1) ;07b (4); 015 (1).
Vancouver I., southern end. ELB Stns., July-August, 1955:
FI (2);P4(l);P6c(3).
ELB Stns., 1970: P702 (2); P712 (7). ELB Stns., 1975: P3a
(2) ; P5a (2); P5b (2); P5d (3); P20 (2). ELB Stns., 1976: B3
(l);B13(5);B28(2).ELBStns.,1977:B6a(l);B8(2);Bllb
(l);B19b(2).
Wizard Inlet, D. Kittle Stn. 712, July 28, 1972 - 1 male, 1
female (fig'd specimen) (slide mounts) -i- 1 female, 3 im.
Barkley Sound, Broken I. group, C. Lobban coll., July 7,
1971 - 1 female; Ibid.. July 9-10 specimens. Bordelais I.,
from sponge at LW level, R. J. Anderson coll, June 26, 1976
- 1 male (slide mount).
WASHINGTON-OREGON.
Coastal localities. ELB Stns., July-August, 1966: W22 (1);
W40 (8); W58 (-15 ); W60 (6).
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
112
FIG. 34. Micropleustes nautilus (J. L. Barnard). Female ov (3.1 mm). Wizard Inlet, B. C.
AMPfflPACIFICA VOL II NO. 1. AUG. 31, 1995
113
KEY TO SPECIES OF MICROPLEVSTES OF THE NORTH PACIFIC REGION
1. Gnathopods, propod elongate, length of lower margin -2Xpropod depth; palm of propod short, length
less than half that of posterior margin; maxilla 1 , inner plate bare; inner ramus of uropods 1 shorter than
peduncle 2
—Gnathopods, propod not elongate, length less than twice depth; propod palm normal, length more than
half postenor margin, maxilla 1 inner plate with single apical seta; uropods 1, inner ramus not shorter
than peduncle ,,
2. Gnathopod 1, carpus distinctly longer than carpus of gnathopod 2; coxal plates 1-4 only slightly deeper
than corresponding body plates; peraeopods 5-7, segment 4 wide, width = length; telson length about
twice width, hnguiform in shape m. longimanus (p. 1 17)
—Gnathopod 1, carpus about equal to that of gnathopod 2; coxal plates 1-4 very deep, much deeper than
corresponding body plates; peraeopods 5-7, segment 4 normal, length distinctly greater than width; tel-
son length about 3 X width, apex narrowly rounding m. nautiloides, n. sp. (p. 1 13)
3. Peraeopod 7, segment 4 postero-distally nearly totally overhanging segment 5 ... M, behningi (p. 1 15)
Peraeopod 7, segment 4 less broad, postero-distally overhanging segment 5 by 1/2 to 2/3 4.
4. Gnathopods, palm of propod distinctly shorter than posterior margin; postero-distal palmar angles with
two distinct groups of spines; telson regularly narrowing distally M. nautilus (p.l 1 1)
—Gnathopods, palm of propod about equal in length to posterior margin, postero-distal angle with two
tight clusters of spines appearing almost as one group; telson, margins constricted medially
behningioides (p. 116)
Coos Bay, Oregon, K. E. Conlan Stn. 08-23 - 2 females, 8
other specimens.
Diagnosis. Female ov (3.2 mm): Body and coxal plates
medium deep. Head, eye round, black. Antenna 1 medium,
peduncle 1 large, length> segments 2 & 3 combined; flagellum
14-segmented. Antenna 2, slightly longer than 1, peduncular
segment 4 & 5 subequal; flagellum 14-segmented.
Upper lip with broad apical V-cleft; lobes asymmetrical.
Lower lip, inner lobes shallow, outer lobes smoothly ovate,
oblique. Mandible, molar very small apex rounded; spine
row with 7-9 medium, distally pectinate blades; cutting edge
of incisor with 7-8 unequal teeth; palp segment 3 with 9 inner
marginal pectinate spines and 1 long terminal seta; left
lacinia 8-dentate. Maxilla 1, inner plate with single apical
seta, palp segment 1 with single “shoulder” seta; segment 2
slightly broadest medially, apex with 4 spines. Maxilla 2,
inner plate slightly broadened distally, inner margin with 2
plumose setae. Maxilliped, inner plate with 2 inner marginal
spines and 2 apical teeth; outer plate medium, narrowing to
rounded apex, with 2 slender curved spines; palp, dactyl
slender minutely pectinate, not longer than segment 3.
Coxa 1 broadest distally. Coxa 5, lobes shallow.
Gnathopod 1, carpus short, deeper than long; propod short-
rectangular, length -1 .5 X depth, with proximal cluster of 2
stout median facial setae; palmar margin short, convex,
postero-distal angle with cluster of 5 spines; hind margin
nearly straight, with distal cluster of 2 spines; dactyl weakly
setulose behind. Gnathopod 2 subsimilar, propod slightly
heavier and deeper than in gnathopod 1.
Peraeopods 3 & 4 relatively short and stout, segment 4
slightly broadened; dactyls short. Peraeopods 5-7 closely
homopodous in size and form; bases broad, rounded behind,
postero-distal lobe medium deep; segment 4 slender, postero-
distal lobe overhanging segment 5 by half its length; dactyls
medium, length about 1/2 segment 6.
Pleon plate 3, hind comer not acuminate. Uropodl slen-
der, rami subequal, with 1 -2 marginal spines. Uropod 2, rami
subequal, slightly shorter than peduncle. Uropod 3, outer
ramus short, with 3-4 marginal spines, length - 1 .5 X each of
peduncle and outer ramus.
Telson medium, slightly narrowing distally to rounded
apex, penicillate setae distal.
Distribution. From SE Alaska to middle and southern
California, intertidal to shallow depths (5 m), associated
with under-rock algal and sponge communities.
Taxonomic commentary. Morphological variations
were noted in O’Clair material from Alaska, and in ELB
material at Stns. F*7 1 2 and W40, but were not considered sig-
nificant at the species level.
Micropleustes nautiloides, new species
(Fig. 35)
Parapleustes species "A" J. L. Barnard, 1969b: 203?
Material examined:
BRITISH COLUMBIA.
Southern Vancouver!.: ELB Stn. P712, Off Hanes L, Trevor
Channel, under boulders and algal mats, LW level, July 2 1 ,
1970 - 4 males, 2 females, 2 im.
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
114
FIG. 35. Micropleustes nautiloides, new species. Female ov (2.9 mm). Sunset Bay, Oregon.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
115
WASHINGTON-OREGON.
Coastal Localities. ELB Stn. W40, Mukkaw Bay, at Sooes
Pt., from bedrock walls and under boulders, LW level, July
31, 1966 - 9 specimens. Sunset Bay, south of Charleston,
Coos Co., K. E. Conlan Stn. 06-06, in Rhodomela larix^ July
8, 1986 - female (2.9 mm) Holotype (slide mount), CMN
Cat. no. NMCC 1995-0074; Ibid.. Stn. 06-03 - 3 females (to
3.1 mm) (1 slide mount), Paratypes, CMN cat. No.
NMCC 1995-0075; Ibid.. Stn. 06-12 - 9 females ov, 3 imm;
Ibid. . Stn 08-6 - 2 im.
Diagnosis. Female ov (2.9 mm): Body and coxal plates
deep. Head small, flat-rounded, black. Antennae short.
Antenna 1, peduncular segment 1, length = segments 2 & 3
combined; flagellum 11 -segmented. Antenna 2, slender,
slightly the longer, flagellum 1 1 -segmented.
Upper lip deep, with narrow apical V-notch; lobes
nearly symmetrical. Lower lip inner lobes deep, outer lobes
large, oblique. Mandible, molar medium, apex sharply
rounded; spine row with 7-9 stout distally pectinate blades;
cutting edge of incisor with 7 unequal teeth; palp segment 3
with elongate basal “A” seta, inner margin with 9 pectinate
spines; left lacinia 8-dentate. Maxilla 1, inner plate small,
lacking apical set; palp segment 1 with single “shoulder seta;
palp segment , narrowing, with 4 apical spines. Maxilla 2,
inner plate broad, with 2 inner marginal plumose setae,
maxilliped inner plate large, narrowing distal with 2 inner
marginal spines, and 3 apical marginal short spines; outer
plate relatively tall, with single curved spine at subconical
apex; dactyl nearly straight, minutely pectinate, not longer
than segment 3.
Coxal 1 little expanded distally, hindcorner with 3 small
cusps. Coxae 2-3, depth ~2X width, hind comers each with
3 small cusps. Coxa 4, width = depth. Coxa 5 , lobes deep.
Gnathopod 1, carpus longer than deep, hind lobe shallow,
short; propod slender, elongate, length ~2X depth, palmar
margin short, oblique convex, postero-distal angle with
group of 4-5 spines, one distinctly largest; hind margin
straight, with distal cluster of 2 short spine and a few cleft-
tipped setae; dactyl short, weakly setulose behind. Gnathopod
2 closely subsimilar, propod slightly stouter.
Peraeopods 3 & 4, slender; dactyls medium. Peraeopods
5-7 homopodous; segment 4 relatively short, broad, postero-
distal process overhanging 2/3 of short segment 5; dactyls
large, length > 1/2 segment 6. Peraeopod 5 slightly shortest;
basis broadest, rounded behind; bases of peraeopods 6 & 7
less expanded, hind margin nearly straight.
Pleon plate 3, lower margin convex, hind comer acute,
produced. Uropods 1 & 2 rami shorter than peduncle,
distally narrowing. Uropod 2, outer ramus distinctly the
shorter. Uropod 3 ordinary, inner ramus with 3 marginal
spines. Telson elongate linguiform, narrowing to sharply
rounded apex; penicillate setae distal.
Distributional ecology. From central British Columbia
to southern Oregon, possibly central California, intertidally
and inimediately subtidal, in algal mats (Rhodomela) and
Phyllospadix clumps, of lotic high salinity waters.
Etymology. A combining form of “nautilus” + “oides”
in reference to the overall similarity of this species to
Micropleustes nautilus.
Taxonomic commentary. Micropleustes nautiloides
is taxonomically closer to M. longimanus than to M. nautilus
(see Fig. 38, p. 118). Parapleustes sp. "A*' of Barnard
(1969b) may be this species.
Micropleustes behningi (Guijanova)
(Fig. 36)
Neopleustes behningi Gurjanova, 1938; 315, fig. 30.
Pleustes behningi Guijanova, 1951: 641, fig. 438.
Parapleustes behningi Barnard & Karaman, 1991: 650
(part). — Ishimaru, 1994: 54 (part?).
Parapleustes behningi Ishimam, 1984: 407, figs. 3-9.
Diagnosis, (mainly after Gurjanova, 1951). Female (1.5
mm): Body and coxal plates short, deep. Head, eye
subquadrate, black. Antennae very short. Antenna 1 , ped-
uncular segment 1 stout, length ~ 2X segments 2 & 3 com-
bined; flagellum 8-segmented. Antenna 2 stout, slightly the
longer; peduncular segment 4 & 5 very short; flagellum 8-
segmented.
Upper lip with narrow epistome; labrum, lobes nearly
symmetrical. Lower lip broad, shallow, outer lobes ovate,
nearly vertical. Mandible, molar short, apex bluntly rounded;
spine row with 7-8 uneven blades, distally thick, proximally
short, slender; cutting edge of incisor with 6(?) irregular
teeth; left lacinia 7-8 dentate. Maxilla 1, inner plate small,
with short apical seta; palp slender, segment 1 lacking
shoulder seta; segment 2 slender, with 3? apical spines.
Maxilla 2, inner plate small, little broadened distally, with
single short inner margin plumose seta Maxilliped, inner
plate regular; outer plate short, with 2 curved spines at round-
ed apex; palp, dactyl stout, slightly longer than segment 3.
Coxae 1-4 relatively deep, narrow. Coxa 1 not expanded
distally, hind Comer with single stout cusp. Coxa 2, distal
margin straight, hind comer with 4-5 distinct cusps. Coxa 4
deeper than broad. Gnathopod 1, carpus short, depth >
length; propod medium long, length -1.5 X depth, palmar
margin short, oblique, nearly straight; postero-distal angle
with cluster of 3 stout spines; hind margin straight, with
distal spine; dactyl strong, minutely setulose behind.
Gnathopod 2, somewhat similar, but carpus slightly shorter,
hind lobe deeper and narrower than in gnathopod 1; propod
more elongate and more slender; length - 2X depth.
Peraeopods 3 & 4 slender, margins of segments 4-6
weakly spinose; dactyl strong, > 1/2 segment 6. Peraeopods
5-7 relatively short; bases medium broad, hind margin convex,
with 6-8 broad crenulations; segment 4 short, postero-distal
process elongate, nearly totally overhanging short segment
5 by 80%; dactyls large.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
116
FIG. 36. Micropleustes behningi (Gurjanova). Female (4.0 mm). Japan Sea. (after Gurjanova, 1951).
Micropleustes behningioides, new species
(Fig. 37)
Parapleustes behningi Ishimaru, 1984: 407, fig. 4. — Barnard
& Karaman, 1991; 650 (part). — Ishimaru, 1994: 54.
Diagnosis. Female (5.9 mm). Body short, compact,
coxal plates deep. Head, eye round, medium large. Antenna
1, peduncular segment 1 short < 2 & 3 combined; flagellum
long, relatively stout, 19-segmented. Antenna 2 shorter,
peduncular segments 4 & 5 short, subequal; flagellum 16-
segmented.
Upper lip regular, lobes slightly asymmetrical. Lower
lip inner lobes, deep, outer lobes large, oblique. Mandible,
molar prominent, slender, apex subacute; spine row with 9
short stout blades; cutting edge of incisor with 8 unequal
teeth; palp segment 3 with short, proximal "A" seta, and 10?
inner marginal pectinate “D” spines; left lacinia with 7(?)
teeth. Maxilla 1, inner plate with single apical plumose seta;
palp segment 1 with 2 "shoulder" setae; segment 2, surface
finely setulose, apically with 4-5 short spines. Maxilla 2,
inner plate short, broadly expanded, inner margin with 2
unequal plumose setae. Maxilliped, inner plate medium,
with few distal facial setae, and 4 apical marginal spines;
outer plate short, apex narrowly rounded, with 2 slender
spines; palp, dactyl stout, nearly straight, not longer than
segment 3.
Coxa 1-3 medium broad, deep. Coxa 1 slightly broadened
distally, hind comer with 1-2 minute cusps. Coxae 2 & 3,
hind comer with 3 minute cusps. Coxa 4 deeper than broad.
Coxa 5 lobes deep. Gnathopod 1, carpus short, deep, hind
lobe narrow; propod short, length ~1.5X width; palmar
margin relatively long, about equal to posterior margin,
convex, oblique, postero-distal angle with 3 spines; dactyl
minutely setulose behind. Gnathopod 2 subsimilar; carpus
slightly shorter and deeper; propod slightly expanding distally .
Peraeopods 3 & 4 stout, 3 distinctly the larger; segment
4 broadened abmptly, with subparallel margins; dactyls
medium strong. Peraeopods 5-7 short, subsimilar; bases
moderately expanded, hind margins gently convex, minutely
crenulate; hind lobes deep; segment 4 broadened, nearly as
wide as deep, postero-distal lobe 2/3 overhanging short
segment 5; dactyls stout.
Pleon plate 2 , hind comer rounded; pleon plate 3 hind
comer acuminate. Uropods 1 & 2 short, little or not exceeding
uropod 3. Uropod 1, rami and peduncle subequal in length.
Uropod2, outerramus distinctly the shorter. Uropod 3, outer
ramus shorter, length barely 1/ inner ramus.
Telson slender, “pinched” medially, narrowing to
rounded apex; penicillate setae distal.
Etymology. A combining form of the species name
“behningi “ and the suffix "oides ", like the regionally co-
occurring species M. behningi (Gurjanova, 1938).
AMPHIPACIFICA VOL 11 NO. 1. AUG. 31, 1995
117
Type material. Ishimam, 1984, figs. 3-7: Female "a"
(5.9 mm), Holotype, Samani, Hokkaido; Ibid-, fig. 8: Male
"e" (4.0 mm), AUotype, Oshoro, Hokkaido. Collections of
the Faculty of Science, Hokkaido University.
Distribution. Eastern Sea of Japan and southern Hok-
kaido, among andSargos^w/n, LW-0.5 m depth.
Taxonomiccommentaiy. Micropleustes behningioides
is readily separable from M. behningi (Guijanova, 1938),
and appears morphologically closer to M. nautilus (see key,’
p. 113; also fig. 34, p. 112 ).
Parapleustes longimanus Ishimam, 1984: 438, figs. 25-28.
—Barnard & Karaman, 1991: 650.— Ishimam, 1994: 54.
Diagnosis. Female (2. 9 mm); Body short, compact,
coxal plates medium deep. Antennae short, slender, subequal.
Antenna 1, peduncular segment 1 short, length < segments
2 & 3 combined; accessory flagellum broadly conical, with
4 apical setae; flageUum 8-segmented. Antenna 2, peduncular
segments 4 & 5 slender, subequal; flagellum 8-segmented.
Upper lip shallowly V-cleft apically, lobes nearly
symmetrical. Lower lip, inner lobes deep, outer lobes small
ovate, oblique. Mandible, molar process, short, conical;
AMPHIPACMCA VOL II NO. 1. AUG. 31, 1995
118
FIG. 38. Micropleustes longimanus (Ishimaru). Female (2.9 mm). Japan, (after Ishimaru, 1984).
spine row with 6-7 short blades; cutting edge of incisor with
6-7 unequal teeth; palp segment 3 with 5 inner marginal
pectinate “D" spines; left lacinia 6-7-dentate. Maxilla 1,
inner plate small, lacking apical seta; palp segment 1 lacking
“shoulder” seta; segment 2 narrowing distally, apex with 3-
4 slender spines. Maxilla 2, inner plate slightly shorter than
outer plate, little broadened, with 1 short inner marginal
plumose seta. Maxilliped, inner plate very short, with 1 inner
marginal stout seta, apex with 2 stout and 2 slender spines;
outer plate very short, subtruncate apex with 2 slender
spines; palp, dactyl curved shorter than segment 3.
Coxae 1-4, lower margins rounded. Coxa 1 slender,
hind comer with single small cusp. Coxae 2-3, lower border
minutely crenulate, hind comer with single cusp. Coxa 4
deeper than wide. Coxa 5, lobes deep. Gnathopodl, carpus
slender, hind lobe very small, length ~2X depth; propods
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
119
slender, length ~3X depth, margins subparallel, palmar margin
very oblique, very short, postero-distal angle with single
cluster of 3 spines (one large); dactyl short, inner margin with
5 short curved setules. Gnathopod 2 subsimilar, except
carpus and propod slightly shorter and deeper.
Peraeopods 3 & 4, segments 4-6 relatively stout, 4 not
broadened; dactyl medium. Peraeopods 5-7 very short, closely
subsimilar; bases broad, lower hind lobes very deep, hind
margins gently convex; segment 4 expanded, broader than
deep, postero-distal lobe nearly totally overhanging short
segment 5; segment 6 stout, with 2 anterior marginal spines;
dactyl medium.
Pleon plate 3, hind comer squared. Pleopods, peduncles
stout, outer margins short-spinose; rami short, 12-segmented.
Uropods 1 & 2 slightly exceeding uropod 3. Uropod 1 , rami
subequal weakly marginally spinose. Uropod 2, outerramus
slightly the shorter. Uropod 3, outer ramus short, length
-60% inner ramus. Telson short, slightly narrowing distally
to broadly rounded apex; penicillate setae marginally
subapical.
Distribution. The species is known from inshore
shallows of the mainland and Japanese coast of the Sea of
Japan.
Taxonomic commentary. Micropleustes longimanus
is distinctive in nearly every character state, but in balance
appears closest to Af. nautiloides ofthe North American Pac-
ific region.
Dactylopleustinae, Bousfield & Hendrycks
Dactylopleustinae Bousfield & Hendrycks, 1994: 38.
Type Genus. Dactylopleustes Karaman & Barnard, 1979,
monotypy.
Diagnosis. A monotypic group of primitive but second-
arily specialized commensal and/or parasitic pleustids.
Rostmm short. Eyes large, reniform. Antennae short,
pediform. Accessory flagellum minute.
Upper lip, notch shallow, lobes only slightly asymmetri-
cal. Lower lip with deep, distinct inner lobes. Mandible,
molar rounded, non-triurating; palp segment 2 short, seg-
ment 3 swollen, lacking baso-facial CA") setae ; right lacinia
lacking; Maxilla 1, outer plate short, wide, with 9-16
pectinate spine-teeth; inner plate with 1 apical seta; palp
large, terminal segment broad. Maxilla 2, plates short,
subequal. Maxilliped, plates small, weakly armed; palp
segments short; dactyl pectinate.
Coxae 1-4 deep, 1 shortest. Gnathopods with elongate
carpus and propod, longer in gnathopod 2; palmar margins
short, lacking median tooth, hind margin setose.
Peraeopods 3-7 short; dactyls short, inner margins finely
crenulate or pectinate. Peraeopods 5-7 basically homopodous;
coxae regularly and strongly postero-lobate; bases broad.
Pleon plates regular, unmodified. Urosome 2 not oc-
cluded dorsally. Uropods 1 & 2 broad-lanceolate, rami sub-
equal, broad-lanceolate. Uropod 3 medium, rami unequal.
Telson keel proximally.
Coxal gills saclike on peraeopods 2-4, plate-like on 5
& 6 .
Taxonomic commentary. This monotypic group (con-
sisting to date of three species in one genus) was formerly
assigned to the genus Parapleustes based on the non-triturat-
ing molar and ordinary form of the maxillipedal palp. How-
ever, the unusual mixture of plesiomorphic and apomorphic
character states justified elevation of the genus Dactylople-
ustes to subfamily ranking (Bousfield & Hendrycks, 1994).
Dactylopleustes Karaman & Barnard
Parapleustes Tzvetkova 1975: 121 (part).
Dactylopleustes Karaman & Barnard, 1979: 112.— Barnard
& Karaman, 1991: 647.
Type species. Parapleustes echinoicus Tzvetkova, 1975,
original designation
Species,Dactylopl€ustesechinoides, new species (p. 121);
D. (Apodactylopleustes) obsolescens Hirayama, 1988.
Diagnosis. Body small, smooth above, lysianassiform;
coxae deep, legs short. Head, rostrum short, about equal to
broadly rounded anterior head lobe; inferior antennal sinus
shallow. Antenna 1 not longer than antenna 2, segment 2
short, segment 3 very short, flagellum shorter than peduncle;
Antenna 2, flagellum shorter than peduncle.
Mouthparts highly modified. Lower lip, inner lobes tall,
outer lobes large, oblique to nearly horizontal. Mandible,
molar forming a smoothly rounded protuberance beneath 6-
8 slender blades; left lacinia with 6-7 rounded teeth; palp
slender; segment 1 short, segment 2 weakly setose; segment
3 with few pectinate inner marginal setae. Maxilla 1, outer
plate short, broad, apical spines slender, innermost strongest.
Maxilla 2, outer plate with heavy spinelike apical setae.
Maxilliped, plates weakly armed; inner plate lacking distal
“button” spines, outer plate, inner margin concave, apex
weakly spined; palp short, segment 2 shortest, segment 3
longest, with medio-distal row of spines; dactyl slender.
Coxal plates 1-4 very deep, broad, much deeper than
body plates; coxa 1 distinctly smallest, but not expanded
distally; hind cusps 2-5 per plate, small. Gnathopods small,
short, subequal, subsimilar, non sexually dimorphic; bases
slender, anterior margin setose (more strongly in Gnathopod
1); merus rounded distally; carpus shallow- setose behind,
length about equal to propod; palm very short, convex, with
few short spines at postero-distal angle, long hind margin
with groups of pectinate setae; dactyl short, smooth.
Peraeopods 3-7 short, segmental margins short-spinose;
dactyls very short, body heavy, inner margin nearly straight,
micro-crenulated. Peraeopods 5-7 regularly homopodous,
coxae very deep, hind lobes rounded below; bases broad,
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
120
KEY TO SPECIES OF DACTYLOPLEUSTES
1. Eyes large, deep, reniform; mandibular palp, segment 2 distinctly longer than segment 1; coxa 1 dist-
inctly shorter than coxa 2; telson elongate; uropods 1 & 2 not modified 2.
— Eyes medium, ovate, few large facets; mandibular palp slender, segment 2 little longer than 1; coxa 1
slightly shorter than coxa 2; uropods 1 & 2 (male), inner ramus short, broad, weakly armed
D. (Apodactylopleustes) obsolescens (p. 123)
2. Maxilla 1, outer plate with 9 apical spine teeth; peraeopod 5, basis with angular postero-distal lobe;
mandibular palp, segment 3 broad, with 7 inner marginal pectinate setae; maxilliped palp, segment 2
subequal to 1, dactyl thick, tip pectinate; gnathopod bases nearly bare of setae . D, echinoicus (p. 120)
— Maxilla 1, outer plate with 15 slender apical spine-teeth; peraeopod 5, basis smoothly rounded behind;
mandibular palp, segment 3 slender, with 5 inner marginal setae; maxilliped palp, segment 3 shorter
than either 1 or 3, dactyl slender, acute, not conspicuously pectinate; gnathopods 1 & 2, basis strongly
setose anteriorly D. (Neodactylopleustes) echinoides (p. 121)
evenly rounded behind.
Pleon side plates medium deep, broad, smooth below,
hind comers acuminate. Pleopod peduncles short, raim with
reduced numbers of segments, not sexually dimorphic.
Uropods 1 & 2 short, stout; rami suramceolate, margins
serially spinose , tips not spinose . Uropod 3 , peduncle short,
stout, rami broad-lanceolate, inner ramus distinctly the larger.
Coxal gills largest on peraeopods 4 & 5, smallest on
peraeopod 6.
Taxonomic commentary. The three component species
of the genus are sufficiently distinct to justify separate
generic status. Although Hirayama (1988) recognizes D.
obscolescens as a distinct subgenus, Apodactylopleustes
(see key above), further subdivision must await analysis of
more extensive material in which new taxa are anticipated.
Gnathopod 1 weakly subchelate; basis slender, bare; carpus
and propod slender, subequal; hind margin of propod with 3
groups of setae. Gnathopod 2 , segment 5 lacking hind lobe,
segment 6, hind margin strongly setose, palm very short,
oblique, dactyl short.
Pereopods 3 & 4, segment 5 < 4, hind margins with short
spines; dactyl short, body with 5-6 prominent posterior
pectinations, unguis slender, curved. Peraopods 5-7, coxae
relatively deep ; bases expanded to different degrees , 5 sharply
angled behind, 7 very broad, rounded, smooth behind; segment
5 shorter than 4; dactyls with small marginal pectinations.
Pleon plates 1-3, hindcomer slightly acuminate. Uropod
3 stout, rami broad; inner ramus almost equal to peduncle
slightly longer than half outer ramus; outer margin of the
outer ramus bare, inner margin with 4 spines.
Telson short almost parallel-sided; apex rounded,
unarmed.
Dactylopleustes echinoicus (Tzvetkova)
(Fig. 39)
Parapleustes echinoicus Tzvetkova, 1975:122, fig, 1.
Dactylopleustes echinoicus Karaman & Barnard, 1979:
1 12. — Barnard & Karaman, 1991 : 647. .
Diagnosis. Female (5.0 mm): Head, rostrum small,
shorter than lateral lobes. Eyes moderate, reniform, black.
Antennae short, 1<2; segments of the peduncle and flagellum
shortened and broad. Flagellum of antenna 1 of 8 segments,
of antenna 2 of 5 segments.
Upper Up, lobes slightly asymmetrical. Mandible, spine
row with 12 slender short blades; incisor 7-dentate; palp
strong; segment 3 longest, with 7 inner marginal pectinate
"D" spines. Maxilla 1, palp segment 2 with 5 apical spines,
segment 1 lacking shoulder seta. Maxilla 2, plates subequal
Maxilliped, inner plate with 3 apical button spines; outer
plate short, with stout apical spine snd slender seta; palp
segment 3 slender, dactyl short, broad, with apical inner
marginal pectinations.
Coxal plates 1 and 2 rectangular, lower margin convex,
hind comer with 2 cusps. Coxal plate 4 deeper than broad.
Distributional ecology. Known only from Bering Is-
land (Commander Islands, off the east coast of Kamchatka),
reef south of Nikol’skoye village.
D. echinoicus is an obligate symbiont of the sea urchin
Strongylocentrotus polyacanthus. The peraeopod dactyls
are modified for holding the cmstacean onto the body of the
sea urchin, as if “wedged in”, and to move around the
movable spines on the surface of the test.
Taxonomic commentskry, Dactylopleustes echinoicus
is phyletically more primitive than the other two species of
the genus subsequently described from Asiatic and North
American coast (pp. below). The dactyls of this genus are
adaptive to a lifestyle of clinging to the spines and surfaces
of sea urchin tests. A less sophisticated form of grasping
dactyl was noted in Commensipleustes commensalis (Shoe-
maker) (p. 82). In that species, the dactyl and expanded
spinose propod of peraeopods 3-7 form a subchelate claw-
like mechanism that enables the amphipod to cling to the
pleopods of the spiny lobster Panulirus interruptus. Such
morphological specializations underscore the high degree of
adaptive radiation within subfamily Parapleustinae that is
associated with a commensal lifestyle.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
121
/ MX 2 / ^__v^;D CTYLX) ' MXPD
Fro. 39. Dactylopleustes echinoicus (Tzvetkova). Female (5.0 mm). Bering Sea. (after Tzvetkova. 1975)
DactylopUmte.echino^es , new species 14 long slender distally curved apical spines; palp
^ broad, With 6 Stout apical spines. Maxilla 2, plates short,
dactylopleustes echinoicus Au%tm 1985- 592? Rpm»rH A *2 heavy apical spines. Maxilliped
KaramaC 1991: 647X^1? 1985.592?-Ban,ard& mner plate short, apex sloping inward, with 3 minute button
spines; outerplate slender, inner margin excavate, apex with
Material 2 setae; palp segment 2 short, 3 with
BRITISH COLUMBIA pectinations near base of thin pectinate dactyl.
Northern Vancouver I • ELB Stn Nlfi Port 1 distinctly shorter than 2, hind comer with 4
1 Qo< rtnon ^ Setae, palm very short, oblique, overhung by stout dactyl.
1995-0080.
Diagnosis. Femaleov (3. 3mm); Head, rostrum as long
as lateral head lobe. Eye deep reniform, black. Antenna very
short. Antenna 1 peduncle 3 not larger than basal flagellar
segment, flagellum 5-segmented. Antenna 2, flagellum 5-
segmented.
Upper lip, median notch sharp, shallow, lobes nearly
- ' ' 1 — > “ ■ -'“““a ovwui uaci^i.
Onathopod 2, basis less strongly setae; carpus longer,
propod subrectangular, palm distinct, strongly convex,’
nearly vertical, hind margin with 3 setal clusters.
Peraeopods 3 & 4, margins of bases lined with short
setae; dactyls short, stout, inner margins with 10+ minute
pectinations. Peraeopods 5-7 closely homopodous, bases
broadly rounded behind; segment 4 widening distally;
equal. Lowerlip,innerlobedeep,n;rrow broadly rounded behind, segment 4 widening distally;
nearly horizontal. Mandible molar large, broadly rounded; beL”d ‘^^'*®'’°'^''“®'>'P«‘=*“a'« Coxa6deep
spinerow with? slender blades; incisor 8-dentate;leftlacinia Plenn h' zt a j
8-9 dentate; palp segment 2 relatively long; segment 3 with l * ' ^’^"‘*‘=°™®>'P’'od“ced, acuminate. Uropod
4 inner marginal pectinate "D” spines. Maxilla fouter plate mar.' * "I’ “ peduncle,
P nes.MdXllia i, outerplate margins strongly spinose. Uropod 3, inner ramus heavy.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
122
Taxonomic & distributional commentary. The host
echinoid has not been determined precisely. However, the
sea urchin Strongyocentrotus purpuratus occurred com-
monly at the type locality . The echinoid fauna of the region
is diverse (Ricketts & Calvin, 1968) and would indicate that
several other host-specific species of Dactylopleustes may
yet be discovered in the North American Pacific region.
thick, margins with 4-5 spines; outer ramus with 3 spines on
each margin.
Telson relatively long, length 2X width, apex smoothly
rounding.
Etymology, Combining the suffix "oides" - like, or sim-
ilar to, the type species D. echinoicus.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
123
Dactylopleustes (Apodactylopleustes) obsolescens, Hira-
yama, 1988: 44, figs. 269-271. — Ishimaru, 1994; 54.
Diagnosis. Male? (2.0 mm): head, rostrum equal to
lateral head lobes. Eye oval, large, orange. Antennae relat-
ively long. Antenna 1, peduncular segment 3 larger than
adjacent flagellar segment; flagellum 6-segmented. Antenna
2, peduncular segments 4 & 5 slender, subequal ; flagellum 5-
segmented.
Lower lip, outer lobes nearly vertical. Mandible, molar
process evanescent spine row with 5 short blades; incisor 7-
8 dentate; left lacinia 8-9 dentate; palp segment 2 very short;
segment 3 long and slender with 1 -2 inner marginal pectinate
“D” spines. Maxilla 1, outer plate with 11 apical spines;
palp, terminal segment apically truncate, with 5 spines!
Maxilla 2, outer plate much the stouter, with 3-5 apical
spines. Maxilliped, inner plate apically truncate, lacking
button spines; outer plate slender, inner margin excavate;
palp segment 2 short, distally pectinate, dactyl pectinate. *
Coxa 1 not noticeably shorter than 2, hind comer with 2
cusps. Coxae 2-3 with 2-3 hind cusps. Coxa 4 relatively
broad, hind process curved upwards. Gnathopod 1, basis
weakly setose; carpus stronger than propod, dactyl stout.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
124
overhanging short, vertical palm. Gnathopod 2, basis nearly
bare; propod rectangular, slightly longer than carpus, dactyl
overhanging short vertical palm, hind margin with 2 groups
of setae.
Peraeopods 3 & 4, hind margins of segment 4-6 with
regular spines, dactyl finely pectinate behind. Peraeopods 5-
7 irregularly homopodous, bases unevenly expanded, hind
margins nearly straight, 6 relatively narrow, 7 broadest, hind
lobes deep; segment 4 broad; segment 5 short, 6 relatively
long; dactyls thick, anterior margins very finely pectinate.
Pleon plate 3 hind comer strongly produced acuminate.
Uropods relatively stout, rami short, broad, especially outer
ramus, much shorter than peduncle, margins weakly spinose.
Uropod 3, inner ramus, margins each with 3 spines; outer
ramus, our margin with 2 pines, inner margin bar. Telson
medium short, length 1.7 X width, apex evenly rounded.
Distribution. Ariake Sea (1 specimen only).
Taxonomic commentary. Dactylopleustes obsolescens
is clearly distinct from echinoicus, but more closely similar
to echinoides. It is distinctive in the unlike form of peraeopods
5-7, the short, weakly armed uropods, and the very elongate
mandibular palp segment 3.
Pleusirinae Bousfield & Hendrycks, 1994
Pleustidae Gurjanova 1972: 135, 138 (key) (part).— Barn-
ard & Karaman, 1991; 649.
Pleusirinae Bousfield & Hendrycks, 1994; 40.
Type genus. Pleusirus Barnard, 1969b, original des-
cription.
Diagnosis. Body small, slender, dorsally smooth;
urosome 2 occluded dorsally. Head, rostrum short, deflexed,
anterior head lobe broadly rounded. Eye rounded. Antennae
slender, medium, antenna 1 the longer. Antenna 1 , peduncles
2 & 3 short; accessory flagellum minute, apex setose; an-
tenna 2, peduncle medium strong.
Mouthparts strongly modified. Upper lip broad, lobes
asymmetrical. Lower lip, inner lobes deep, narrow. Mandi-
ble, molar reduced to a large smooth lobe; spine row short,
blades short; left lacinia multi-dentate (9-10); right lacinia
lacking; palp slender, segment 2 longest; segment 3 shorter,
lacking baso-facial seta; segment 1 elongate. Maxilla 1,
inner plate small, bare; outer plate with 9 apical spines; palp
slender, facially pilose, apex weakly armed. Maxilla 2,
plates small, weakly setose-spinose. Maxilliped, inner plate
short, with few apical and inner marginal spines; outer plate
narrow, colunmar; palp large, subcheliform; segment 3 wid-
est medially, not produced beyond base of slender dactyl.
Coxal plates 1-4 increasing in size posteriorly, rounded
below, lacking hind cusps. Gnathopods 1 & 2 slender,
subequal, “eusiroidean” in form, not sexually dimorphic;
carpus elongate, hind lobe shallow; propod subovate, palm
long, lacking median tooth; posterior angle with 2 spine
clusters.
Peraeopods 3-7 slender; dactyls short. Peraeopods 5-7
closely homopodous in size and form; bases broad, rounded
behind; segment 4 little overhanging segment 5 behind.
Pleon plates 1-3, hind comers acuminate. Pleopods
strong, not sexually dimorphic. Uropods 1-3 slender, rami
elongate, spinose. Telson elongate, keeled proximally,pem-
icillate setae median.
Coxal gills narrow, saclike on peraeopods 2 & 3, plate-
like on peraeopods 4-6, increasing posteriorly.
Taxonomic commentary. The subfamily appears
allied with the subfamily Parapleustinae in most character
states, especially of the mouthparts. It is unique in the
eusiroidean form of the gnathopods, the generally reduced
form of maxillae 1 & 2, the inflated, distally smooth
mandibular molar; elongate mandibular palp segment 1 ; and
the semi-subchelate form of the maxilliped palp.
Pleusirus J. L. Barnard
Pleusirus J. L. Barnard, 1969b: 204.— Gurjanova, 1972:
135. — Barnard & Karaman, 1991: 649.
Type species. Pleusirus secorrus Barnard, 1969b: 204.
Subspecies. Pleusirus secorrus asiaticus Kudrjaschov
& Tzvetkova, 1975, original designation.
Diagnosis. With the characters of the subfamily , and in
addition: Antenna 1, peduncular segment 1 with postero-
distal process; flagellar segments, posterior marginal aesth-
etascs paired, prominent.
Mandibular blades thick, distally pectinate; incisor 7-8-
dentate, third tooth largest. Maxilla 1, palp segment 1 with
"shoulder" seta. Maxilla 2, inner plate not broadened, lack-
ing inner marginal plumose seta. Maxilliped, inner plate
with stout inner marginal and apical spines.
Gnathopods 1 & 2, bases slender, margins not strongly
setose; propod, hind margin smooth; dactyl slender.
Peraeopods 5-7, coxae deep, postero-lobate, hind lobes
rounded, segment 5 not longer than 4.
Uropods 1 & 2, inner ramus longer than peduncle. Uro-
pods 2 & 3, outer ramus short. Telson rounded, penicillate
setae median.
Male; Antennal segments with prominent aesthetascs; per-
aeopods 5-7 relatively slender; dactyls relatively long, slender,
nearly straight.
Taxonomic and distributional commentary. The genus
encompasses two forms, one a subspecies of the other, one
on the Asiatic and the other on the North American Pacific
coast.
AMPHIPACIFICA VOLII no. 1. AUG. 31, 1995 125
Pleusirus secorrus J. L. Barnard, 1969b: 204, fig. 56.—
Guijanova, 1972: 135, 138 (key). — ^Austin, 1985: 592.
Staude, 1987: 379. — Barnard & Karaman, 1991; 650.
Material examined.
ALASKA. 46 specimens (all females, afew subadults) from
18 localities, as follows:
Southeastern Alaska: ELB Stns., June-July, 1961: A3 (8);
A6 (12); A8 (1); A48 (1); A75 (3); A80(7); A8 1 (1); A92 (6);
BRITISH COLUMBIA. 252 specimens (including 1 male?)
at 59 localities, as follows;
Queen Charlotte Islands. ELB Stns., July- Aug 1957- H14
(2);W4a(2);W4b(3); E5(1);E25(1);W8(7); W9(1V W 1 1
(7);W12a(3).
Northcentral coast. ELB Stns., July, 1964: HI (15)- H3 (2)-
H5 (30); H7 (12); H8 (2); HIO (2); H12 (8); H26 (5)- H 23
(1)H29 ( 1); H30 (10); H47 (1); H48 (2); H50 (3); H53 (20+)-
H57 (1); H65 (6). ELB Stn., 1959: N22 (2).
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
126
Vancouver Island, north end: ELB Stns., July, 1959: 01 (1);
05 (3); 01 1 (3); 013 (7); 015 (7); V5 (2); V7 (3); VI 1 (1);
V17 (2); V18 (1); N 1 1 (1); N16 (1).
Vancouver Island, south end: ELB Stns., July-Aug., 1955:
FI (6); F4 (1); P2 (1); P7 (1). ELB Stns., 1970: P715 (1);
P716(2); P718(13);P719(1). ELB Stns., 1975:P5b(2);P5c
(1); (20(4). ELB Stns., 1976:B3(2);B4(2);B5(1); B7(10).
ELB Stns., 1977: B7a ( (8); Bllb (1); B14 (1); B19b (2);
B21b (3). ELB Stn. 015, Box I., Wickaninnish Bay, in
Phyllospadix clumps, algal mats, over bedrock, LW level,
Aug. 16, 1959 - female ov (3.7 mm) (slide mount) (fig’d
specimen) + 7 other females.
Duncan Bay, Middle Pt., barge, 3-4 m dive, tZ/va &bryozo-
ans,P.Shawcoll.,Seot5, 1987- 1 male (fig’d) + 6 specimens.
WASHINGTON-OREGON. 22 specimens at 3 localities, as
follows:
Coastal localities: ELB Stns, July-Aug., 1966: W40 (18);
W42 (2); W58 (2).
Diagnosis. With the characters of the genus and sub-
family. The subspecies Khudrjaschov& Tzvetkova,
1975, may prove to be morphologically, if not ecologically,
distinct, but western Pacific material was not re-examined in
this study.
Distributional ecology. On the North American Pacific
coast this species occurs from southeastern Alaska, through
British Columbia, Washington and Oregon, to southern Cal-
ifornia. It occurs commonly from the extreme LW level to
to depths of 25 m, in clumps of Phyllospadix, algae, and in
organic debris, often on shelly sand bottoms, mainly at cold,
high salinity, outer coast locations.
Pleusirus secorrus asiaticus Kudrjashov & Tzvetkova
PleusirussecorrusasiaticusK.udTi3shov&TzyQlko\3i, 1975:
1314, fig. 2A. — Tzvetkova Kudryashov, 1985: 1.
Pleusirus secorrus Ishimaru, 1985d: 103. — Ishimaru, 1994:
54.
Taxonomic and distributional commentary. This form
was collected from clumps of algae and Phyllospadix at
stations on South Sakhalin I., in the southern part of the Sea
of Okhotsk, and south to Pos'yet Bay in the Sea of Japan. It
is also recorded from amongst fronds of Tichocarpus carin-
atus, Cytoseira sp., and Laminaria japonica. Females with
eggs and early juveniles occur in July and August.
The Asiatic form of P. secorrus has been synonymized
by Ishimaru (loc. cit.) and Barnard & Karaman (loc. cit.).
However, taxonomic differences noted in the original
description (Kudrjashov & Tzvetkova, loc. cit.) suggest that
a different species may be involved. In order to justify
recognition of asiaticus as a full species, it is recommended
that the original material be re-examined, redescribed and
fully figured.
Systematic and Biogeographical Analyses
This study treats the systematics and distributional
ecology of 29 species of the gammaridean subfamily
Parapleustinae that occur along both Asiatic and North
American coasts of the North Pacific region. A modified
phenetic cluster analysis, and corresponding cladistic analysis,
indicated the Parapleustinae to be the most advanced
phyletically of the 12 recognized subfamilies within family
Pleustidae (Bousfield & Hendrycks, 1994). We conclude
here by commenting in greater detail on aspects of the
morphology and lifestyle and on biogeographical rel-
ationships of its component genera and species.
The seven genera of Parapleustinae appear similar in the
overall plesiomorphic form of the body and appendages.
Greatest morphological diversity occurs in the numbers and
kinds of mandibular blades, in the cutting edges of the
incisors and left lacinia, and to lesser extent in the form and
armature of the gnathopods. Sexually dimorphic gnathopods
occur, uniquely in this subfamily, among the Pleustidae.The
taxonomic and phyletic relationships of the seven genera are
not readily apparent through general inspection, but may be
clarified through numerical analysis of characters and
character states of those body features (Fig. 43,' page 127).
For this purpose, a modification of the UPGMA cluster ana-
lysis system of Sneath and Sokal (1973) is utilized. The 20
selected taxonomic characters and corresponding character
states are outlined in Table I. The overall degree of
evolutionary advancement of the genus is provided by a
plesio-apomorphic (P.-A.) index, derived by summing the
values for each character state for each species, as explained
in previous analyses (e.g. Bousfield and Hendrycks, 1994;
Jarrett & Bousfield, 1994).
The phenogram of morphological relationships (Fig.
43) suggests that the seven genera are not very closely
similar, at least in the characters considered. Only two
generic pairs, the North American endemic Gnathopleustes-
Trachypleustes, and the broadly temperate-subtropical
Incisocalliope-Commensipleustes cluster at similarities of
70% or better. The pan-Pacific genera Micropleustes and
Parapleustes cluster at 60-65% with the latter complex.
However, the mainly North American genus Chromopleustes
stands in isolation, with less than 50% similarity to the other
generic groupings. The P.-A. index is slightly less than 20
(less than 50% of maximum apomorphy) for all genera
except the relatively advanced genus Incisocalliope where
the value is 30 (75% of maximum). These values may
indicate that the members of the Parapleustinae are
evolutionary “stable”, i. e., they remain “locked in” to
exploitation of specialized shoal-water niches (e.g., within
Phyllospadix communities) of the North Pacific region that
either do not exist elsewhere (e.g., in the cold-temperate
North Atlantic or antiboreal regions), or else are inaccessible
because of past and present physical and physiological
barriers to dispersal.
A phenogram of morphological relationships within
species of the genus Incisocalliope is provided in Figure 44,
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
127
B
t
40
1
38
>-
H
36
CC
<
34
i
32
(/)
Id
30
1-
<
28
(/)
26
n
Id
1-
24
O
<
cc
22
<
X
20
o
Q
18
Ld
cc.
16
<
a.
1
14
1
12
18
17
19
17
10
19
30 P.-A. INDEX
GENERA
A - Ch ro m o p / eu s t es
B -Gnathop/eustes
C - Trachyp/eustes
D - Mi cro p / eu s tes
E - Parap/eu stes
F - Co m m en sip / eu s tes
G - in ci s o cai i i o p e
75 “
f£
50
0)
FIG. 43. PHENOGRAM OF GENERA OF SUBFAMILY PARAPLEUSTINAE
p. 129. The analysis is based on 16 characters and cor-
responding character states orvided in Table II, p. 1 30. The
8 species cluster into three main assemblages at similarities
of 65-75%, viz., a relatively primitive newportensis-bairdi
group, a very advanced dilatatus-makiki group, and a
slightly less advanced derzhavini-aestuarius group of two
closely similar species pairs. These three major assemblages
cluster at about the 50% similarity level and appear therefore
not closely related. The newportensis-bairdi subgroup,
known only from inshore waters of southern California, is
especially plesiomorphic in character states of themouthparts
and peraeopods, but the gnathopods are powerfully
subchelate, and relatively advanced.
Possible biogeographical relationships of the dilatatus-
makiki group are discussed below (pp. 129-30). The close
similarity of the regionally co-occurring sibling species pair
of derzhavini and is not unexpected. However,
the 90% morphological similarity between the widely
separated Asiatic Pacific and the North American
Atlantic aestuarius is unexpected and defies ready explan-
ation.
Similar analysis of the North American endemic genus
Gnathopleustes suggests th^t G. pugettensis,a simplex, G.
pachychaetus and G. den form a relatively advanced and
closely related species complex that collectively have a
continuous distribution from southeastern Alaska to southern
California (Table II, p. 129). Gnathopleustes trichodus ond
G. JerratMj are relatively primitive morphologically, isolated
phyletically and more restricted distributionally. The
Trachypleustes species complex, with highly modified
mandibular blades, and possibly more speciose than here
considered, is more northerly in distribution. At least one
species attains the Bering Sea region but has not yet been
taken on the Asiatic coast. The Micropleustes complex is
more speciose on the Asiatic coast. However, the most
common North American species of this genus, M nautilus,
has die widest range of any parapleustin in the North American
Pacific region, from the Bering Sea to southern California.
With respect to subfamily Pleusirinae, Pleusirus secorrus,
including its Asiatic subspecies, is the only known member
of family Pleustidae to occur in all nine biogeographic zones
of the North Pacific region. Subfamily Dactylopleustinae is
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
128
TABLE I. CHARACTERS AND CHARACTER STATES: GENERA OF PARAPLEUSTINAE
CHARACTER STATES
CHARACTERS
Plesiomorphic
0
Intermediate
1
Apomorphic
2
1. Antennal, peduncular
long
short
segment 2: segment 1
short
2. Antenna 2, peduncular
long
segments 4 & 5
3. Upper lip, lobes
shallow
subequal
deep, markedly
asymmetrical
4. Lower lip, inner lobes
deep
narrow
shallow
broad
5. Mandibular blades
numerous (>10)
(7-8)
few (~5)
long, slender
short, acute
short, flat
6. Mandible, palp segment 3,
12-15
8-10
-5
number of “D” spines
10 +
7. Mandibular left lacinia,
5-6
7-9
number of teeth
11
15+
8. Maxilla 1, outer plate.
9
number of apical spines
1
9. Maxilla 1, palp segment 1,
0
2
number of setae
10. Maxilla 2, width of
narrow
broad,
inner plate
L>W
L-W
11. Maxilliped, inner plate,
7-10
0-2
number facial setae
large
12. Maxilliped, segment 3
short
13. Gnathopods 1 & 2,
weak
strong
size of propod
shallow
deep
14. Gnathopods 1 & 2,
elongate
short
size of carpus
shallow
deep
15. Gnathopods 1 & 2, degree
none
marked
of sexual dimorphism
16. Gnathopods 1 & 2,
strong
vestigial
lacking
palmar tooth
3-4
17. Coxae 1-3, number of
posterior marginal spines
none
18. Peraeopods 3-7, size of
subequal
5 distinctly
shorter
segment 5: segment 4
19. Uropods 1 & 2,
ramal spines
numerous
strong
few
weak
20. Telson shape
short
broad
elongate
narrow
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
129
I
>
H
(L
32
30
28
< 26
(/)
LU
I-
<
I-
(0
CE
LU
I-
o
<
a:
<
X
o
o
lU
cc
<
Q.
24
22
20
18
16
14
12
10
INCiSOCALLtOPE
A -
n e wp orten si 8
B -
bairdi
C -
diiatatu s
D -
makiki
E -
nipponensis
F -
derzh a vini
G -
aestuarius
H -
fi tiai is
75
QC
<
50
(/)
FIG. 44. PHENOGRAM OF SPECIES OF INCISOCALUOPE
represented on Asiatic and North American coasts by the
species pair of Dactylopleustes obsolescens and D. echin-
oides, respectively. Although these echinoid-commensal
species probably have geographical ranges similar to their
host species of Strongylocentrotus, locality records are yet
insufficient for meaningful biogeographical analysis.
Biogeographical considerations
The subfamily Parapleustinae is essentially endemic to
continental coasts of the North Pacific region (Table III, p.
131). The distribution of five of the seven genera (i.e.
Chromopleustes, Micropleustes, Gnathopleustes,
Trachypleustes and Commensipleustes) is essentaially cold-
temperate, whereas Parapleustes is subarctic-boreal, and
Incisocalliope is temperate-subtropical. Of its 28 described
species here included, only three species have been recorded
elsewhere, Viz., Parapleustes gracilis from arctic-subarctic,
marine parts of the N orth Atlantic and western Arctic Oceans ;
Incisocalliope aestuarius from temperate estuaries of the
western North Atlantic, and 1. makiki from the Hawaiian
Islands in the south-central subtropical North Pacific.
In the northern North Pacific region, 16 species of
parapleustins, representative of all seven genera, occur along
the coasts of continental North America, whereas only nine
species, in four genera, have been recorded to date from the
Asiatic continental coast (Table III). In the eastern North
Pacific, species numbers are largest along the coast of British
Columbia ( 1 0 species in each of zones 5, 6) but decrease both
northwards and southwards. In the western North Pacific,
the fauna of the Asiatic coast is less well known, but most (7)
parapleustin species occur in the northern part of the sea of
Japan, and fewer (3) in the cold waters of the Sea of Okhotsk
to the north. Although no single species has yet been
recorded from both continental coasts, the Bering Sea contains
five species in four genera, and presumably provides the
major pathway of gene flow between the two continental
populations.
However, North American species of Incisocalliope
(i.e. newportensis and bairdi) are widely separated from
their Asiatic counterparts (e.g.filialis, derzhavini, nipponensis
and dilatatus) and are relatively primitive morphologically
(Fig. 44, above). These facts would suggest that these
populations have been separated geographically for a
considerable time, perhaps since the early Palaeogene (50-
60 m.y.b.p.) when northern Pacific sea levels were lower,
and marine climates were warmer and more equable (Adams,
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
130
TABLE n. CHARACTERS AND CHARACTER STATES: INCISOCALUOPE SPECIES
CHARACTER
CHARACTER STATE
Plesiomorphic
Intermediate
Apomorphic
0
1
2
1. Antenna 1, number
30+
~25
<15
flagellar segments
2. Antenna 2, number
20+
10-15
-5
flagellar segments
3. Mandible, palp seg. 3,
~10
-5
number “D” setae
4. Mandible, number
10
5
of blades in row
5. Maxilla 1, palp 2,
4
0
number facial setae
6. Maxilliped, inner pi..
4+
3
2
apical “button” spines
7. Gnathopodl, basis.
nearly bare
strong
ant. marginal setation
throughout
8. Gnathopod 1, carpal
broad
narrow
lobe
shallow
deep
9. Gnathopod 1, posterior
3
0
margin, no. setal gps.
10. Peraeopods 3 & 4,
subequal
markedly
segments: segment 4
shorter
11. Peraeopods 5-7,
broad
narrow
width of basis
width-depth
width« depth
12. Peraeopods 5-7
deep, reaching
shallow
hind lobe depth
segment 4
13. Uropod 1, peduncle
numerous
few (4)
outer marginal spines
(10+)
basal position
14. Uropod 2, length
long
markedly
of outer ramus: inner
subequal
shorter
15. Uropod 3, length
long
short
outer ramus: inner
(75%+)
(-60%)
16. Telson, rel. form
long, slender
short, broad
1981). During that period, and perhaps later, early members
of the genus may have penetrated via a southern waterway
(now blocked by the Panamanian isthmus) to the western
Atlantic region where Incisocalliope aestuarius remains a
sole survivor. The widely disjunct distributions of the
filialis-aestuarius species pair is also reminiscent of somewhat
similar disjunct distributions of the coastal aquatic arachnid
order Xiphosurida (Savory, 1964), and the coastal aquatic
reptilian genus Alligator (Carr, 1963). Both these groups
may have been biogeographically continuous between
southern Asia and North America during early to middle
Cretaceous times, via a Tethyan marine pathway outlined by
Howarth (1991). Such a hypothesis is unlikely for para-
pieustins and related subfamily members of which no relict
modern representatives now exist along that route and/or are
physiologically unsuited to those marine thermal regimes.
The presence in the remote Hawiaiian islands of Incisocalliope
makiki, closely related to /. dilatatus of the Asiatic group.
is anomalous. However, /. makiki may prove to be a relict
species, representative of an ancestral group from Japan that
penetrated the Hawaiian Archipelago, perhaps during the
early Tertiary. They may have survived by “island hopping”
as the volcanic islands of the chain successively emerged in
the east and eroded away in the west (Howarth & Mull,
1992).
In summary, subfamily Parapleustinae encompasses
diverse, relatively advanced morphotypes and specialized
lifestyles of pleustid micropredators. These occupy various
niches within the Phyllospadix and sessile invertebrate
communities of intertidal and shallow water habitats, almost
exclusively within the North Pacific region. Although this
fauna is believed relatively ancient, and probably originated
during Mesozoic times (Bousfield, 1982b), the long-term
stability of regional shallow-water ecosystems and their
marine climates may have been major factors in dampening
evolutionary thrust in other directions.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
131
TABLE III . DISTRIBUTION OF GENERA AND SPECIES OF PARAPLEUSTINAE
IN THE NORTH PACIFIC REGION.
TAXON
BIOGEOGRAPHIC
ZONE
1
2
3
4
5
6
7
8
9
1 . Chromopleustes
C.johanseni
X
JC
C. oculatus
X
X
X
JC
C. lineatus
X
X
X
JC
2. Micropleustes
longimanus
X
X
behningioides
X
behningi
nautilus
X
X
X
X
X
X
X
X
nautiloides
X
X
X?
3. Parapleustes
ishimarui
americanus
gracilis *
JC
X
X
X
X
4. Gnathopleustes
serratus
X
X
X
X
X
pachychaetus
X
X
X
X
trichodus
X
simplex
X
pugettensis
X
X
X
X
X
7
den
X
X
5. Trachypleustes
trevori (+ varieties)
X
X
X
X
9
vancouverensis
X
6. Commensipleustes
commensalis
7
X
7. Incisocalliope
filialis
X
derzhavini
X
nipponensis
X
dilatatis
makikU
newportensis
X
X
bairdi
aestuarius+
X
* N. Atlantic-subarctic; ! Hawaiian Islands; + N. American Atlantic temperate
BIOGEOGRAPHIC ZONES;
1. Sea of Japan; 2. Sea of Okhotsk; 3. Bering sea and Aleutians; 4. Southeastern Alaska; 5. Northern
B. C.; 6. Southern B. C.; 7. Wash.-Oregon; 8. Northern California; 9. Southern & Baja California.
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
132
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LEGEND FOR FIGURES
A1
antenna 1
MX 1 -
maxilla 1
A2
antenna 2
MX2 -
maxilla 2
AC FL -
accessory flagellum
BR.
coxal gill
MXPD -
maxilliped
BR PL -
brood plate
O.P. -
outer plate
CX
coxal plate(s)
P3-P7 -
peraeopods 3-7
DACT -
dactyl
PLEOS -
pleosome
DORS -
dorsal view
PLP -
palp
EPl-3 -
pleon plates 1-3
RT
right
GNl
gnathopod 1
SET -
seta(e)
GN2
gnathopod 2
SP
spine
HD
head
T
telson
I.P.
inner plate
U1-U3 -
uropods 1-3
I.R.
inner ramus
UROS -
urosome
LFT
left
X
magnified
LL
lower lip
(f
male
MD
mandible
9
female
AMPHIPACIFICA VOL II NO. 1. AUG. 31, 1995
134
Additions to Amphipacifica, Voi. 1(4), 1995.
The following catalogue numbers have been provided
through the courtesy of the Invertebrate Curatorial Unit,
Canadian Museum of Nature, Ottawa, pertinent to the
following paper:
Bousfield, E. L., & E. A. Hendrycks, 1995. The amphipod
superfamily Eusiroidea in the North American Pacific Region.
1. Family Eusiridae: systematics and distributional ecology.
Amphipacifica I (4): 3-59.
l .Eusiruscolumbianus Bousfield & Hendrycks, 1995, pp.
10-11, fig. 5.
Female (5.2 mm), Holotype (slide mount). CMN Cat.
no. NMCC1995-0001.
2. Rhachotropis calceolata Bousfield & Hendrycks, 1995,
pp. 26-27, fig. 16.
Female ov (8.7 mm), Holotype (slide mount). CMN
Cat. no. NMCC1995-0005.
3. Rhachotropis boreopacifica Bousfield & Hendrycks,
1995, p. 29, fig. 17.
Female br. I (10.5 mm), Holotype (slide mount). CMN
Cat. no. NMCC 1995-0006.
Female (unspecified), Paratype. CMN Cat. no.
NMCC1995-0007.
4. Rhachotropis minuta Bousfield & Hendrycks, 1995, p.
35, fig. 22.
Female ov (3.8 mm), Holotype (slide mount). CMN
Cat. no. NMCC1995-0008.
2 other females, ELB Stn. P3, West Bay, B. C., Nov. 2,
1977, Paratypes. CMN Cat. no. NMCC 1995-0009.
5. Rhachotropis conlanae Bousfield & Hendrycks, 1995, p.
37, fig. 23.
Female (4.5 mm), Holotype (slide mount). CMN Cat.
no. NMCC1995-0010.
Female (4. 1 mm), Bocade Quadra, southeastern Alaska,
June 27, 1989, Paratype. CMN Cat. no. NMCC1995-001 1 .
Catalogue numbers remain pending for the following
species:
1, Eusirus hirayamae Bousfield & Hendrycks, 1995, p. 10,
fig. 3.
Male (6.5 mm), Holotype. Ariake Sea, Japan.
Original material described and figured (as E. longipes
Boeck) in: Hirayama, A., 1985. Publ. Seto Mar. Biol. Lab.
30; 29, figs. 142-147. Collections of the Amakusa Marine
Biological Laboratory (AMBL), Amakusa, Japan.
l.Cleonardomoirae Bousfield & Hendrycks, 1995, pp. 15-
17, fig. 7.
Female ov. (7.0 mm), Holotype. Institute of Ocean
Sciences (lOS), Sidney, B. C.
3. Rhachotropis barnardi Bousfield & Hendrycks, 1995,
pp. 29-31, fig. 18.
Male (3.3 mm), Holotype. Unspecified Paratypes.
Original material briefly described and figured (as R. clemens
Barnard) in; Barnard, J. L., 1971; Smiths. Contr. Zool. 61:
10, figs. 6, 7. Off Oregon, 200 m. Collections of the United
States National Museum, Washington, D. C.
4. Rhachotropis americana Bousfield & Hendrycks, 1995,
p. 40, fig. 26.
Female (11.3 mm), Holotype (slide mount); male (9.5
mm), AUotype); 5 females, 1 male, Paratypes. RBCM/
CMN Stn. 91-1-119. Collections of the CMN, Ottawa.
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